3-frequency branching circuit, branching circuit and radio communication equipment

ABSTRACT

A 3-frequency branching circuit in the past could not be used for a system wherein a TDMA method such as GSM and DCS and a W-CDMA method such as UMTS are mixed. The 3-frequency branching circuit equipped with branching means having first and second internal terminals, an antenna terminal of connecting to an antenna, a low-pass filter connected between the first internal terminal and the antenna terminal, and a high-pass filter connected between the second internal terminal and the antenna terminal, a switching circuit of switching between GSM TX and GSM RX, a switching circuit of switching between DCS TX, DCS RX and a third internal terminal, and a duplexer connected to the third internal terminal.

This application is a U.S. National Phase Application of PCTInternational Application PCT/JP01/05414.

TECHNICAL FIELD

The present invention relates to a 3-frequency branching circuit, abranching circuit and radio communication equipment capable of switchinga signal of a portable telephone for instance.

BACKGROUND ART

In recent years, as for a 3-frequency branching circuit in mobilecommunication equipment, attention is focused on a system of selecting atransmitting and receiving frequency of three frequencies in the systemsof GSM, DCS and PCS with one portable telephone or the like due to theexpanding user base or globalization of the systems, and moreover,attention is paid to possibility of implementing a smaller size and alower price as to the mobile communication equipment such as theportable telephone.

Hereafter, an example of the 3-frequency branching circuit in the pastwill be described by referring to the drawings. Moreover, FIG. 56 showsan equivalent circuit diagram of the 3-frequency branching circuit inthe past.

In FIG. 56, a transmitting circuit side 2301 as one side has an anode ofa first diode P2301 connected thereto via a first capacitor elementC2301, and a contact A has a cathode connected thereto.

Furthermore, the anode side of the first diode P2301 has a controlterminal 2302 connected thereto, and the control terminal 2302 plays arole of switching a transmitting and receiving signal of one of the3-frequency branching circuits.

In addition, a receiving circuit side 2303 as one side has an anode of asecond diode P2302 connected thereto via a second capacitor elementC2302, and a first strip line L2301 is connected to one end of the anodeside of the second diode P2302 having a cathode connected to its groundside, and then the other end of the first strip line L2301 is connectedto the contact A.

Furthermore, a transmitting and receiving circuit 2304 as one sideconnected to the contact A is connected to an antenna terminal 2305 viaa low-pass filter and a third capacitor element C2303.

In addition, a transmitting circuit side 2306 as the other side has ananode of a third diode P2303 connected thereto via a fourth capacitorelement C2304, and a cathode is connected to a contact B. Furthermore,the anode side of the third diode P2303 has a control terminal 2307connected thereto, and the control terminal 2307 plays a role ofswitching the transmitting and receiving signal of one of compositeswitches.

In addition, a contact C on the other receiving circuit side has ananode of a fourth diode P2304 connected thereto via a fifth capacitorelement C2305, and a cathode is connected to its ground side, and asecond strip line L2302 is connected to one end of the anode side of thefourth diode P2304, and then the other end of the second strip lineL2302 is connected to the contact B.

Furthermore, a transmitting and receiving circuit 2309 as the other sideconnected to the contact B is connected to the antenna terminal 2305 viaa high-pass filter HPF and the third capacitor element C2303.

Furthermore, a high-frequency receiving circuit side 2308 has an anodeof a fifth diode P2305 connected thereto via a sixth capacitor elementC2306, and in addition, a control terminal 2311 is connected to theanode side of the fifth diode, and the control terminal 2311 plays arole of switching two receiving signals of the 3-frequency branchingcircuit.

In addition, the other high-frequency receiving circuit side 2310 has ananode of a sixth diode P2306 connected thereto via a seventh capacitorelement C2307, and a cathode is connected to its ground side, and athird strip line L2303 is connected to one end of the anode side of thesixth diode P2306, and then the other end of the third strip line L2303is connected to the contact C.

Operation of the 3-frequency branching circuit constituted as above willbe described.

First, the cases of transmitting and receiving a low frequency will bedescribed.

In case of transmitting the low frequency, the first diode P2301 andsecond diode P2302 will be in an on state by applying a positive voltageto the control terminal 2302.

At this time, the capacitors C2301, 2302 and C2303 cut a DC component,and so the current does not run to each terminal. In addition, atransmitting signal transmitted from a transmitting terminal 2301 is nottransmitted to the receiving side because impedance of the first stripline L2301 becomes an infinite size due to the second diode P2302connected to the ground side.

For that reason, the transmitting signal is transmitted to the antennaterminal 2305 via the low-pass filter LPF.

Next, on receiving, the first diode P2301 and second diode P2302 are inan off state in order to apply no voltage to the control terminal 2302so that the receiving signal is transmitted from the antenna terminal2305 to the receiving terminal 2303 via the low-pass filter.

Next, the cases of transmitting and receiving a high frequency will bedescribed.

The third diode P2303 and fourth diode P2304 will be in the on state byapplying a positive voltage to a control terminal 2307.

At this time, the capacitors C2303, 2304 and C2305 cut a DC component,and so the current does not run to each terminal. In addition, thetransmitting signal transmitted from a transmitting terminal 2306 is nottransmitted to the receiving side because the impedance of the secondstrip line L2302 becomes the infinite size due to the fourth diode P2304connected to the ground side.

For that reason, the transmitting signal is transmitted to the antennaterminal 2305 via the high-pass filter.

Moreover, on receiving, the third diode P2303 and fourth diode P2304 arein the off state in order to apply no voltage to the control terminal2307 so that the receiving signal is transmitted from the antennaterminal 2305 to the receiving side. Thus, it can be transmitted to areceiving terminal side C via the high-pass filter.

Next, in case of receiving on a receiving terminal 2308 as one side, novoltage is applied to the control terminal 2307 on receiving asmentioned above.

At this time, the fifth diode P2305 and sixth diode P2306 are put in theon state by applying the positive voltage to the control terminal 2307,but the capacitors C2305, 2306 and C2307 cut the DC component, and sothe current does not run to each terminal.

And the signal transmitted from the antenna terminal 2305 is nottransmitted to the other receiving terminal 2310 because the impedanceof the third strip line L2303 becomes the infinite size due to the sixthdiode P2306 connected to the ground side.

At this time, it is transmitted to the receiving terminal 2308 via thehigh-pass filter.

Next, when receiving on the other, the fifth diode P2305 and sixth diodeP2306 are in the off state in order to apply no voltage to the controlterminal 2307 so that the receiving signal is transmitted from theantenna to the other receiving side.

For this reason, the other receiving signal can be transferred from theantenna terminal 2305 to the receiving terminal 2310 via the high-passfilter.

However, there was a problem that, although the above configuration issuited to the TDMA (Time Division Multiple Access) method such as GSM,DCS and PCS, it cannot be used for a system wherein the TDMA method suchas GSM and DCS and the W-CDMA (Wide-band Code Division Multiple Access)method such as UMTS are mixed.

DISCLOSURE OF THE INVENTION

An object of the present invention is, considering the above problem inthe past, to provide the 3-frequency branching circuit, branchingcircuit and radio communication equipment also usable for a systemwherein the TDMA method and the W-CDMA method assuring high tone qualityand high speed data communication for instance are mixed.

One aspect of the present invention is a 3-frequency branching circuithaving a filter function of passing a transmitting frequency band and areceiving frequency band in each of first, second and third frequencybands, comprising:

first, second and third internal terminals;

an antenna terminal of connecting to an antenna;

branching circuit having a first filter of passing the third frequencyband between the first internal terminal and the antenna terminal and asecond filter of passing the first and second frequency bands betweenthe second internal terminal and the antenna terminal;

a first switching circuit, connected to the first internal terminal, ofswitching between a first transmitting terminal used to transmit thethird frequency band and a first receiving terminal used to receive thethird frequency band;

a second switching circuit, connected to the second internal terminal,of switching among a second transmitting terminal used to transmit atransmitting frequency band of the second frequency band, a secondreceiving terminal used to receive a receiving frequency band of thesecond frequency band, and the third internal terminal used to transmitand receive the first frequency band; and

a duplexer, connected to the third internal terminal, of branching thetransmitting frequency band and the receiving frequency band of thefirst frequency band.

Another aspect of the present invention is the 3-frequency branchingcircuit according to the 1st invention,

wherein the third internal terminal is connected to the branchingcircuit and is also grounded via a diode.

Still another aspect of the present invention is the 3-frequencybranching circuit,

wherein the third internal terminal is connected to the branchingcircuit via the diode in a forward direction when transmitting andreceiving the first frequency band.

Yet still another aspect of the present invention is the 3-frequencybranching circuit,

further comprising a low-pass filter inserted between the branchingcircuit and the second switching circuit.

Still yet another aspect of the present invention is the 3-frequencybranching circuit,

wherein the first receiving terminal and the third internal terminal areconnected to the antenna and are also grounded via the diode in aforward direction and a grounding resistor respectively; and

one resistor is shared as the grounding resistor used for the respectivegroundings.

A further aspect of the present invention is the 3-frequency branchingcircuit,

wherein the first and second receiving terminals are connected to theantenna and are also grounded via the diode in a forward direction and agrounding resistor respectively; and

one resistor is shred as the grounding resistor used for the respectivegroundings.

A still further aspect of the present invention is a branching circuithaving a filter function of passing a transmitting frequency band and areceiving frequency band in each of a first to Nth frequency bands,comprising:

first and second internal terminals;

an antenna terminal of connecting to an antenna;

branching circuit having a first filter of passing n+1-th (2≦n≦N−1) toNth frequency bands between the first internal terminal and the antennaterminal and a second filter of passing the first to the nth frequencybands between the second internal terminal and the antenna terminal;

a first switching circuit, connected to the first internal terminal, ofswitching between the transmitting frequency bands and the receivingfrequency bands of the n+1-th to Nth frequency bands;

a second switching circuit, connected to the second internal terminal,of switching between the transmitting frequency bands of the firstfrequency band and the second to nth frequency bands and the receivingfrequency bands of the second to the nth frequency bands; and

a duplexer of branching the transmitting frequency band and thereceiving frequency band of the first frequency band.

A yet further aspect of the present invention is a 3-frequency branchingcircuit having a filter function of passing a transmitting frequencyband and a receiving frequency band in each of first, second and thirdfrequency bands, comprising:

first, second, third and fourth internal terminals;

an antenna terminal of connecting to an antenna;

branching circuit having a first filter of passing the third frequencyband between the first internal terminal and the antenna terminal and asecond filter of passing the first and second frequency bands betweenthe second internal terminal and the antenna terminal;

a first switching circuit, connected to the first internal terminal, ofswitching between the transmitting frequency band and the receivingfrequency band of the third frequency band;

a second switching circuit, connected to the second internal terminal,of switching and transmitting the second frequency band to the thirdinternal terminal and the first frequency band to the fourth internalterminal;

a third switching circuit, connected to the third internal terminal, ofswitching between the transmitting frequency band and the receivingfrequency band of the second transmitting frequency band; and

a duplexer, connected to the fourth internal terminal, of branching thetransmitting frequency band and the receiving frequency band of thefirst frequency band.

A still yet further aspect of the present invention is the 3-frequencybranching circuit,

wherein that the duplexer has a configuration in which a coaxial typeresonator is used and is comprised of a notch filter and a band passfilter.

An additional aspect of the present invention is the 3-frequencybranching circuit,

wherein the duplexer has the configuration in which a coaxial typeresonator is used, and a signal of a transmitting frequency band istransmitted to the fourth internal terminal via the notch filter, and asignal of a receiving frequency band is transmitted from the fourthinternal terminal via the band pass filter.

A still additional aspect of the present invention is the 3-frequencybranching circuit,

wherein the fourth internal terminal is an internal terminal of amultilayered product.

A yet additional aspect of the present invention is the 3-frequencybranching circuit,

wherein a SAW filter is used for the duplexer.

A still yet additional aspect of the present invention is the3-frequency branching circuit,

wherein the duplexer is comprised of a coaxial type resonator and alayered filter.

A supplementary aspect of the present invention is the 3-frequencybranching circuit,

wherein a coaxial type resonator and a SAW filter are used for theduplexer.

A still supplementary aspect of the present invention is the 3-frequencybranching circuit,

wherein a layered filter and a SAW filter are used for the duplexer.

A yet supplementary aspect of the present invention is a branchingcircuit having a filter function of passing a transmitting frequencyband and a receiving frequency band in each of first to Nth frequencybands, comprising:

first, second, third and fourth internal terminals;

an antenna terminal of connecting to an antenna;

branching circuit having a first filter of passing the n+1-th (2≦n≦N−1)to Nth frequency bands between the first internal terminal and theantenna terminal and a second filter of passing the first to the nthfrequency bands between the second internal terminal and the antennaterminal;

a first switching circuit, connected to the first internal terminal, ofswitching among the frequency bands of the n+1-th to Nth frequencybands;

a second switching circuit, connected to the second internal terminal,of switching and transmitting the second to n-th frequency bands to thethird internal terminal and the first frequency band to the fourthinternal terminal;

a third switching circuit, connected to the third internal terminal, ofswitching among the second to n-th frequency bands; and

a duplexer, connected to the fourth internal terminal, of branching thetransmitting frequency band and the receiving frequency band of thefirst frequency band.

A still yet supplementary aspect of the present invention is a3-frequency branching circuit comprising:

a duplexer having a filter function of passing a transmitting frequencyband and a receiving frequency band in each of first, second and thirdfrequency bands and equipped with first and second internal terminals,an antenna terminal of connecting to an antenna, a first filter ofpassing transmitting frequency bands of the three frequency bands andreceiving frequency bands of the second and third frequency bandsbetween the first internal terminal and the antenna terminal, and asecond filter of passing the receiving frequency band of the firstfrequency band between the second internal terminal and the antennaterminal;

branching circuit, connected to the first internal terminal, ofbranching (1) the transmitting frequency band of the first frequencyband, transmitting frequency band of the second frequency band, andreceiving frequency band of the second frequency band, (2) thetransmitting frequency band of the third frequency band and thereceiving frequency band of the third frequency band;

a first switching circuit of switching between transmitting of the thirdfrequency band and receiving of the third frequency band; and

a second switching circuit of switching between transmitting of thefirst and second frequency bands and receiving of the second frequencyband.

Another aspect of the present invention is the 3-frequency branchingcircuit,

wherein the duplexer has a configuration using a coaxial type resonator,the first filter is comprised of a notch filter and the second filter iscomprised of a band pass filter.

Still another aspect of the present invention is the 3-frequencybranching circuit,

wherein the duplexer has a configuration using a coaxial type resonator,and a notch filter and a low-pass filter are constituted between thefirst internal terminal and the antenna terminal.

Yet still another aspect of the present invention is the 3-frequencybranching circuit,

wherein the duplexer has a configuration using a coaxial type resonatorbetween the first internal terminal and the antenna terminal, and thesecond filter is comprised of a layered filter.

Still yet another aspect of the present invention is the 3-frequencybranching circuit,

wherein the duplexer has a configuration using a coaxial type resonatorbetween the first internal terminal and the antenna terminal, and a SAWfilter is used for the second filter.

A further aspect of the present invention is the 3-frequency branchingcircuit,

wherein the duplexer has a configuration using a layered filter betweenthe first internal terminal and the antenna terminal, and a SAW filteris used between the second terminal and the antenna terminal.

A still further aspect of the present invention is a 3-frequencybranching circuit comprising:

branching circuit, having a filter function of passing a transmittingfrequency band and a receiving frequency band in each of first, secondand third frequency bands, of branching (1) the transmitting frequencyband and receiving frequency band of the third frequency band, (2) thetransmitting frequency band of the first and second frequency bands andthe receiving frequency band of the first and second frequency bands,having first and second internal terminals, an antenna terminal ofconnecting to an antenna, a first filter of passing the transmittingfrequency band and receiving frequency band of the third frequency bandbetween the first internal terminal and the antenna terminal and asecond filter of passing the transmitting frequency band of the firstand second frequency bands and the receiving frequency band of the firstand second frequency bands between the second internal terminal and theantenna terminal;

a first switching circuit, connected to the first internal terminal, ofswitching between transmitting of the third frequency band and receivingof the third frequency band;

a duplexer, connected to the second internal terminal, having third andfourth internal terminals, a third filter of passing the transmittingfrequency band of the first and second frequency bands and the receivingfrequency band of the second frequency band between the third internalterminal and the second internal terminal, and a fourth filter ofpassing the receiving frequency band of the first frequency band betweenthe fourth internal terminal and the second internal terminal; and

a second switching circuit, connected to the third internal terminal, ofswitching between the transmitting frequency band of the first andsecond frequency bands and the receiving frequency band of the secondfrequency band.

A yet further aspect of the present invention is the 3-frequencybranching circuit,

wherein the duplexer has a configuration using a coaxial type resonator,and the third filter is comprised of a notch filter and the fifth filteris comprised of a band pass filter.

A still yet further aspect of the present invention is the 3-frequencybranching circuit,

wherein the duplexer has a configuration using a coaxial type resonator,and the third filter is comprised of a notch filter and a low-passfilter.

An additional aspect of the present invention is the 3-frequencybranching circuit,

wherein the duplexer has a configuration using a layered filter, wherethe layered filter constituted between the third internal terminal andthe second internal terminal is comprised of a notch filter and thelayered filter constituted between the fourth internal terminal and thesecond internal terminal is comprised of a band pass filter.

A still additional aspect of the present invention is the 3-frequencybranching circuit,

wherein the duplexer has a configuration using a layered filter, wherethe layered filter constituted between the third internal terminal andthe second internal terminal is comprised of a notch filter and alow-pass filter.

A yet additional aspect of the present invention is the 3-frequencybranching circuit,

wherein the duplexer is comprised of a filter using a coaxial typeresonator between the third internal terminal and the second internalterminal, and the fourth filter is comprised of a layered filter.

A still yet additional aspect of the present invention is the3-frequency branching circuit,

wherein the duplexer is comprised of a filter using a coaxial typeresonator between the third internal terminal and the second internalterminal, and the filter constituted between the fourth internalterminal and the second internal terminal is comprised of a SAW filter.

A supplementary aspect of the present invention is the 3-frequencybranching circuit,

wherein the duplexer has the third filter comprised of a layered filterand the fourth filter is comprised of a SAW filter.

One aspect of the present invention is a 3-frequency branching circuitcomprising:

a duplexer having a filter function of passing a transmitting frequencyband and a receiving frequency band in each of first, second and thirdfrequency bands and equipped with first, second and third internalterminals, an antenna terminal of connecting to an antenna, a firstfilter of passing a transmitting frequency band and a receivingfrequency band of the third frequency band between the first internalterminal and the antenna terminal, a second filter of passing thetransmitting frequency band of the first and second frequency bands andthe receiving frequency band of the second frequency band between thesecond internal terminal and the antenna terminal, and a third filter ofpassing the receiving frequency band of the first frequency band betweenthe third internal terminal and the antenna terminal;

a first switching circuit, connected to the first internal terminal, ofswitching between the transmitting frequency band and the receivingfrequency band of the third frequency band; and

a second switching circuit, connected to the second internal terminal,of switching between the transmitting frequency band of the first andsecond frequency bands and the receiving frequency band of the secondfrequency band.

Another aspect of the present invention is the 3-frequency branchingcircuit,

wherein the first filter is formed by a low-pass filter, the secondfilter is formed by a band pass filter, and the third filter is formedby a high-pass filter.

Still another aspect of the present invention is the 3-frequencybranching circuit,

wherein the first filter is formed by a low-pass filter, the secondfilter is formed by a band pass filter, and the third filter is formedby a notch filter.

Yet still another aspect of the present invention (is a branchingcircuit having a first branching circuit having a filter function ofpassing a transmitting frequency band and a receiving frequency band ineach of first to Nth frequency bands, and equipped with first to k-thinternal terminals and an antenna terminal of connecting to an antenna,

wherein the first internal terminal is a terminal of outputting thereceiving frequency band of the first frequency band;

the k-th internal terminal is the terminal of inputting the transmittingfrequency band of the first frequency band and inputting and outputtingthe transmitting frequency bands and the receiving frequency bands ofall or a part of the second to the N-th frequency bands.

Still Yet another aspect of the present invention is the branchingcircuit, further comprising a second branching circuit, connected to thek-th internal terminal, of branching the transmitting frequency band ofthe first frequency band and all or a part of the frequency bands of thesecond to the N-th frequency bands.

A further aspect of the present invention is the branching circuit,

wherein the N is 3 and the k is 2;

the second internal terminal is the terminal of inputting thetransmitting frequency band of the first frequency band and inputtingand outputting the transmitting frequency bands and the receivingfrequency bands of the second and third frequency bands which are all ofthe frequency bands;

a first switching circuit of switching between input of the transmittingfrequency band of the third frequency band and output of the receivingfrequency band of the third frequency band branched by the secondbranching circuit; and

a second switching circuit of switching between the input of thetransmitting frequency band of the first frequency band and thetransmitting frequency band of the second frequency band and the outputof the receiving frequency band of the second frequency band branched bythe second branching circuit.

A still further aspect of the present invention is the branchingcircuit,

wherein the N is 3 and the k is 2;

the third internal terminal is a terminal of inputting the transmittingfrequency band of the first frequency band and inputting and outputtingthe transmitting frequency band and the receiving frequency band of thesecond frequency band which is the part of frequency bands;

the second internal terminal is the terminal of inputting and outputtingthe transmitting frequency band and the receiving frequency band of thethird frequency band which is the remaining frequency band;

a second switching circuit, connected to the third internal terminal, ofswitching between the input of the transmitting frequency band of thefirst frequency band and the transmitting frequency band of the secondfrequency band and the output of the receiving frequency band of thesecond frequency band; and

a first switching circuit, connected to the second internal terminal, ofswitching between the input of the transmitting frequency band of thethird frequency band and the output of the receiving frequency band ofthe third frequency band.

A yet further aspect of the present invention is a branching circuitcomprising:

first branching circuit having a filter function of passing atransmitting frequency band and a receiving frequency band in each offirst to Nth frequency bands, and equipped with first to k-th internalterminals and an antenna terminal of connecting to an antenna, and

wherein the first internal terminal is a terminal of inputting thetransmitting frequency band of the first frequency band;

the k-th internal terminal is the terminal of outputting the receivingfrequency band of the first frequency band and inputting and outputtingthe transmitting frequency bands and the receiving frequency bands ofall or a part of the second to N-th frequency bands.

A still yet further aspect of the present invention is a branchingcircuit comprising:

first branching circuit having a filter function of passing atransmitting frequency band and a receiving frequency band in each offirst to Nth frequency bands, and equipped with first and secondinternal terminals and an antenna terminal of connecting to an antenna;and

second branching circuit having a filter function of passing thetransmitting frequency band and the receiving frequency band in each offirst to N−1-th frequency bands, and equipped with third to k-thinternal terminals and a connection terminal of connecting to the secondinternal terminal,

wherein the first internal terminal is a terminal of inputting andoutputting the transmitting frequency bands and the receiving frequencybands of the N-th frequency bands;

the second internal terminal is a terminal of inputting and outputtingthe transmitting frequency band and the receiving frequency band of thefirst to the N−1-th frequency bands;

the k-th internal terminal is the terminal of outputting the receivingfrequency band of the first frequency band; and

the third internal terminal is the terminal of inputting thetransmitting frequency band of the first frequency band and inputtingand outputting the transmitting frequency bands and the receivingfrequency bands of all or a part of the second to N−1-th frequencybands.

An additional aspect of the present invention is the branching circuit,further comprising third branching circuit, connected to the thirdinternal terminal, of branching the transmitting frequency band of thefirst frequency band and all or a part of the second to N-th frequencybands.

A still additional aspect of the present invention is the branchingcircuit,

wherein the N is 3 and the k is 4;

the third internal terminal is the terminal of inputting thetransmitting frequency band of the first frequency band and inputtingand outputting the transmitting frequency band and the receivingfrequency band of the second frequency band which is all of thefrequency bands;

a first switching circuit, connected to the first internal terminal, ofswitching between the input of the transmitting frequency band of thethird frequency band and the output of the receiving frequency band ofthe third frequency band; and

a second switching circuit, connected to the third internal terminal, ofswitching between the input of the transmitting frequency band of thefirst frequency band and the transmitting frequency band of secondfrequency band and the output of the receiving frequency band of thesecond frequency band.

A yet additional aspect of the present invention is a branching circuitcomprising:

first branching circuit having a filter function of passing atransmitting frequency band and a receiving frequency band in each offirst to Nth frequency bands, and equipped with first and secondinternal terminals and an antenna terminal of connecting to an antenna;and

second branching circuit having a filter function of passing thetransmitting frequency band and the receiving frequency band in each offirst to N−1-th frequency bands, and equipped with third to k-thinternal terminals and a connection terminal of connecting to the secondinternal terminal,

wherein the first internal terminal is a terminal of inputting andoutputting the transmitting frequency band and the receiving frequencyband of the N-th frequency band;

the second internal terminal is the terminal of inputting and outputtingthe transmitting frequency band and the receiving frequency band of thefirst to the N−1-th frequency bands;

the k-th internal terminal is the terminal of inputting the transmittingfrequency band of the first frequency band; and

the third internal terminal is the terminal of outputting the receivingfrequency band of the first frequency band and inputting and outputtingall or a part of the transmitting frequency bands and the receivingfrequency bands of the second to N−1-th frequency bands.

A still yet additional aspect of the present invention is the3-frequency branching circuit,

wherein the branching circuit is constituted by a layered configurationusing the dielectric green sheet.

A supplementary aspect of the present invention is the 3-frequencybranching circuit,

wherein at least one of the first, second and third switching circuits,the duplexer and the first, second and third filters is constituted by alayered configuration using a dielectric green sheet.

A still supplementary aspect of the present invention is the 3-frequencybranching circuit according to any one of the 1st, 8th, 17th, 23rd and31st inventions,

wherein at least one of the branching circuits, first, second and thirdswitching circuits, the duplexer and the first, second and third filtersis constituted by mounting a switching element on a multilayered productusing a dielectric green sheet.

A yet supplementary aspect of the present invention is the 3-frequencybranching circuit,

wherein at least one of the first, second and third switching circuitshas a configuration using a diode.

A still yet supplementary aspect of the present invention is the3-frequency branching circuit,

wherein a GaAs (gallium arsenide) switch is used for at least one of thebranching circuits and the first, second and third switching circuits.

Another aspect of the present invention is the 3-frequency branchingcircuit,

wherein the first frequency band is a frequency band supporting theW-CDMA method.

Still another aspect of the present invention is radio communicationequipment comprising:

an antenna of transmitting and receiving a signal;

a 3-frequency branching circuit; and

signal processing device which processes the signal branched by the3-frequency branching circuit or branching circuit.

Thus, the 3-frequency branching circuit according to the presentinvention has a first internal terminal of a transmitting frequency bandof three frequencies and a receiving frequency band of two frequencies,a second internal terminal of the receiving frequency band of oneremaining frequency, and a third antenna terminal of connecting to theantenna, for instance, where the above described filter makes a duplexerof branching a frequency band wherein a band width of which commonterminal is the third antenna terminal is a broad band and therespective frequency bands are in proximity, the above described firstinternal terminal has a branching filter of branching low and highfrequency bands, a switching circuit of switching transmitting andreceiving is provided to the other end of the low frequency band, andthe switching circuit of switching transmitting and receiving is alsoprovided to the other end of the high frequency band.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a 3-frequency branching circuit accordingto a first embodiment of the present invention;

FIG. 2 is an explanatory view of frequency bands corresponding to GSM,DCS and W-CDMA;

FIG. 3 are an explanatory view (FIG. 3 (a)) of the 3-frequency branchingcircuit (front) and an explanatory view (FIG. 3 (b)) of the 3-frequencybranching circuit (backside) according to the first embodiment of thepresent invention;

FIG. 4 is a circuit diagram of the 3-frequency branching circuitaccording to the first embodiment of the present invention;

FIG. 5 is an equivalent circuit diagram of a duplexer 4 according to thefirst embodiment of the present invention;

FIG. 6 is a circuit diagram of the 3-frequency branching circuit whereinan internal terminal 23 is connected to branching circuit 3 via a diodeD1 according to the present invention;

FIG. 7 is an explanatory view of the 3-frequency branching circuithaving a low-pass filter 11 inserted between the branching circuit 3 anda switching circuit 2 according to the present invention;

FIG. 8 is an explanatory view of the 3-frequency branching circuithaving grounding resistor R shared between the switching circuits 1 and2 according to the present invention;

FIG. 9 are an explanatory view (FIG. 9 (a)) of the 3-frequency branchingcircuit (front) equipped with a SAW filter and an explanatory view (FIG.9 (b)) of the same 3-frequency branching circuit (backside) according tothe present invention;

FIG. 10 are an explanatory view (FIG. 10 (a)) of the 3-frequencybranching circuit (front) equipped with a duplexer on a multilayeredproduct and an explanatory view (FIG. 10 (b)) of the same 3-frequencybranching circuit (backside) according to the present invention;

FIG. 11 are an explanatory view (FIG. 11 (a)) of the 3-frequencybranching circuit (front) equipped with a duplexer inside a multilayeredproduct and an explanatory view (FIG. 11 (b)) of the same 3-frequencybranching circuit (backside) according to the present invention;

FIG. 12 is a circuit diagram of the 3-frequency branching circuitaccording to a second embodiment of the present invention;

FIG. 13 is a perspective view of a layered type duplexer according to athird embodiment of the present invention;

FIG. 14 is an exploded perspective view of the layered type duplexeraccording to the third embodiment of the present invention;

FIG. 15 is an equivalent circuit diagram of the layered type duplexeraccording to the third embodiment of the present invention;

FIG. 16 is a top view of the duplexer combining a coaxial type and thelayered type described in the third embodiment of the present invention;

FIG. 17 is a top view of the duplexer combining the coaxial type and aSAW filter described in the third embodiment of the present invention;

FIG. 18 is a top view of the duplexer combining the layered type and SAWfilter described in the third embodiment of the present invention;

FIG. 19 is an equivalent circuit diagram of the 3-frequency branchingcircuit according to a fourth embodiment of the present invention;

FIG. 20 is a diagram showing an example of a characteristic of abranching filter according to the fourth embodiment of the presentinvention;

FIG. 21 is an equivalent circuit diagram of another form of the3-frequency branching circuit according to the fourth embodiment of thepresent invention;

FIG. 22 is an equivalent circuit diagram of another form of the3-frequency branching circuit according to the fourth embodiment of thepresent invention;

FIG. 23 is a perspective view of the 3-frequency branching circuitaccording to a fifth embodiment of the present invention;

FIG. 24 is a perspective view of another form of the 3-frequencybranching circuit according to the fifth embodiment of the presentinvention;

FIG. 25 is a circuit diagram of the 3-frequency branching circuitaccording to a sixth embodiment of the present invention;

FIG. 26 is an equivalent circuit diagram of the coaxial type duplexeraccording to a seventh embodiment of the present invention;

FIG. 27 is a top view of the coaxial type duplexer according to theseventh embodiment of the present invention;

FIG. 28 is a characteristic view of the duplexer according to theseventh embodiment of the present invention;

FIG. 29 is a perspective view of the layered type duplexer according toan eighth embodiment of the present invention;

FIG. 30 is an exploded perspective view of the layered type duplexeraccording to the eighth embodiment of the present invention;

FIG. 31 is an equivalent circuit diagram of the layered type duplexeraccording to the eighth embodiment of the present invention;

FIG. 32 is a top view of the duplexer combining the coaxial type and thelayered type described in the eighth embodiment of the presentinvention;

FIG. 33 is a top view of the duplexer combining the coaxial type and theSAW filter described in the eighth embodiment of the present invention;

FIG. 34 is a top view of the duplexer combining the layered type and theSAW filter described in the eighth embodiment of the present invention;

FIG. 35 is an equivalent circuit diagram of the 3-frequency branchingcircuit according to a ninth embodiment of the present invention;

FIG. 36 is a characteristic view of the duplexer according to the ninthembodiment of the present invention;

FIG. 37 is a perspective view of the multilayered product of thebranching filter according to a tenth embodiment of the presentinvention;

FIG. 38 is an exploded perspective view of the device (lower half)including a first switching circuit and a second switching circuitaccording to the tenth embodiment of the present invention;

FIG. 39 is an exploded perspective view of the device (upper half)including the first switching circuit and second switching circuitaccording to the tenth embodiment of the present invention;

FIG. 40 is a perspective view of the device integrating the layered typeduplexer of the 3-frequency branching circuit as in the eighthembodiment of the present invention and the multilayered productconstituting the first and second switching circuits as in the tenthembodiment;

FIG. 41 is a perspective view of the device integrating a combination ofa notch filter and a band pass filter as in the eighth embodiment of thepresent invention and the multilayered product constituting thebranching filter and first and second switching circuits as in the tenthembodiment;

FIG. 42 is a perspective view of the multilayered product integrating a1 input-4 output or 1 input-5 output GaAs (gallium arsenide) switch andthe layered type duplexer as in the eighth embodiment of the presentinvention;

FIG. 43 is a perspective view of the multilayered product integratingthe 1 input-4 output or 1 input-5 output GaAs (gallium arsenide) switchand a combination of the notch filter and band pass filter as in theeighth embodiment of the present invention;

FIG. 44 is a circuit diagram of the 3-frequency branching circuitaccording to a fifteenth embodiment of the present invention;

FIG. 45 is an equivalent circuit diagram of the 3-frequency branchingcircuit according to a sixteenth embodiment of the present invention;

FIG. 46 is a perspective view of the multilayered product of thebranching filter according to a seventeenth embodiment of the presentinvention;

FIG. 47 is an exploded perspective view of the device (lower half)including the first switching circuit and second switching circuitaccording to the seventeenth embodiment of the present invention;

FIG. 48 is an exploded perspective view of the device (upper half)including the first switching circuit and second switching circuitaccording to the seventeenth embodiment of the present invention;

FIG. 49 is a circuit diagram of the 3-frequency branching circuitaccording to an eighteenth embodiment of the present invention;

FIG. 50 is an equivalent circuit diagram of the coaxial type duplexeraccording to a nineteenth embodiment of the present invention;

FIG. 51 is a top view of the coaxial type duplexer according to thenineteenth embodiment of the present invention;

FIG. 52 is a characteristic view of the duplexer according to thenineteenth embodiment of the present invention;

FIG. 53 is a perspective view of the layered type duplexer according toa twentieth embodiment of the present invention;

FIG. 54 is an exploded perspective view of the layered type duplexeraccording to the twentieth embodiment of the present invention;

FIG. 55 is an equivalent circuit diagram of the layered type duplexeraccording to the twentieth embodiment of the present invention; and

FIG. 56 is a circuit diagram of the 3-frequency branching circuit in thepast.

DESCRIPTION OF THE SYMBOLS

-   1, 2 Switching circuits (transmitting and receiving switching    circuits)-   3 Branching circuit (branching circuit)-   4 Duplexer-   20 Antenna terminal-   21 to 23 Internal terminals-   11 to 13 Low-pass filters (LPF)

BEST MODE FOR CARRYING OUT THE INVENTION

Hereafter, embodiments of the present invention will be described byreferring to the drawings.

First Embodiment

First, the configuration and operation of a 3-frequency branchingcircuit of this embodiment will be described mainly by referring toFIG. 1. Moreover, FIG. 1 is a block diagram of the 3-frequency branchingcircuit according to this embodiment.

The 3-frequency branching circuit according to this embodiment is atriple-switch 3-frequency branching circuit having a filter function ofpassing a transmitting frequency band and a receiving frequency band ineach of GSM (a third frequency band), DCS (a second frequency band) andW-CDMA (a first frequency band) as shown in FIG. 2, and has switchingcircuits (transmitting and receiving switching circuits) 1 and 2, abranching circuit 3 and a duplexer 4 and also has an appearance as shownin FIGS. 3 (a) to (b). Moreover, FIG. 2 is an explanatory view offrequency bands corresponding to GSM, DCS and W-CDMA. In addition, FIG.3 (a) is an explanatory view of the 3-frequency branching circuit(front) according to this embodiment (explanatory view of an exampleintegrating the switching circuits and branching circuit) and FIG. 3 (b)is an explanatory view of the 3-frequency branching circuit (backside)according to this embodiment.

Next, each element of the 3-frequency branching circuit of thisembodiment will be described in further detail.

The branching circuit 3 has internal terminal 21 and 22, an antennaterminal 20 of connecting to an antenna (ANT), a low-pass filter (LPF)of passing the third frequency band (GSM) connected between the internalterminal 21 and the antenna terminal 20, and a high-pass filter (HPF) ofpassing the first and second frequency bands (DCS and W-CDMA) connectedbetween the internal terminal 22 and the antenna terminal 20.

The switching circuit 1 is connected to the internal terminal 21 for thepurpose of switching between a transmitting terminal T x 1 (GSM TX)utilized for transmission of the third frequency band (GSM) and areceiving terminal R x 1 (GSM RX) utilized for receiving of the thirdfrequency band.

The switching circuit 2 is connected to the internal terminal 22 for thepurpose of switching among the internal terminal 23 utilized fortransmitting and receiving of the first frequency band (W-CDMA), atransmitting terminal T x 2 (DCS TX) utilized for transmission of atransmitting frequency band of the second frequency band (DCS) and areceiving terminal R x 2 (DCS RX) utilized for receiving of a receivingfrequency band of the second frequency band (DCS).

The duplexer 4 is connected to the third internal terminal 23 for thepurpose of switching between transmitting and receiving of the firstfrequency band (W-CDMA) (to be more specific, switching between atransmitting terminal T x 3 (W-CDMA TX) utilized for transmission of atransmitting frequency band of the first frequency band (W-CDMA) and areceiving terminal R x 3 (W-CDMA RX) utilized for receiving of areceiving frequency band of the first frequency band (W-CDMA)).

Next, a circuit configuration of the 3-frequency branching circuit ofthis embodiment will be described by referring to FIG. 4. Moreover, FIG.4 is a circuit diagram of the 3-frequency branching circuit according tothis embodiment.

The transmitting terminal T x 1 is connected to the antenna side via adiode D2 which is in a forward direction when transmitting. In addition,the receiving terminal R x 1 is connected to the antenna side, and isalso grounded via a diode D4 which is in the forward direction.Moreover, a control terminal VC1 is connected to a voltage controlportion (omitted in the drawings) via a resistor R1. In addition, alow-pass filter 12 is inserted between the transmitting terminal T x 1and the anode of diode D2 as a filter of reducing noise (signaldistortion) due to amplification when transmitting by utilizing thetransmitting terminal T x 1.

The transmitting terminal T x 2 is connected to the antenna side via adiode D3 which is in the forward direction when transmitting. Inaddition, the receiving terminal R x 2 is connected to the antenna sidevia a diode D1 which is in the opposite direction (off state) whentransmitting by utilizing the transmitting terminal T x 2 (the diode D1is in the forward direction when receiving by utilizing the receivingterminal R x 2). Moreover, a control terminal VC2 is connected to thevoltage control portion (omitted in the drawings) via a resistor R2, anda control terminal VC3 is connected to the voltage control portion(omitted in the drawings) via a resistor R3. In addition, a low-passfilter 13 is inserted between the transmitting terminal T x 2 and theanode of diode D3 as a filter of reducing the noise due to theamplification when transmitting by utilizing the transmitting terminal Tx 2.

The internal terminal 23 (refer to FIG. 1) is connected to the duplexer4, and is also grounded high-frequency-wise via a diode D5 in theforward direction.

Here, circuit configuration of the duplexer 4 will be described indetail by referring to FIG. 5. Moreover, FIG. 5 is an equivalent circuitdiagram of the duplexer 4 (the duplexer 4 is the substantially same asthe duplexer (refer to FIG. 15) in a third embodiment described later).

The duplexer 4 is comprised of a large number of dielectric layersconsisting of layers A to H (omitted in the drawings). The layer A has afirst ground electrode formed therein. In addition, the layer B hasfirst to fifth resonator electrodes 5302 to 5306 formed therein, and thelayer C has first to second capacitor coupling electrodes 5307 to 5308formed therein. The layer D has third to sixth capacitor couplingelectrodes 5309 to 5312 and first to second strip line electrodes 5313to 5314 formed therein. The layers E to G have seventh to ninthcapacitor coupling electrodes 5315 to 5317 formed therein. Furthermore,the layer H has a second ground electrode 318 formed therein.

An electrode to be the transmitting terminal T x 3 of W-CDMA (refer toFIGS. 1 and 4) is connected to the strip line electrode 5314, and isgrounded by the ground electrode via the capacitor coupling electrode5317. The other end of the strip line electrode 5314 is connected to oneend of the capacitor coupling electrode 5312, and the capacitor couplingelectrode 5312 is connected to the resonator electrode 5302 via thelayers C to D. The other end of the capacitor coupling electrode 5312 isconnected to one end of the capacitor coupling electrode 5311, and thecapacitor coupling electrode 5311 is connected to the resonatorelectrode 5303 via the layers C to D. The other end of the capacitorcoupling electrode 5311 is connected to one end of the strip lineelectrode 5313, and one end of the strip line electrode 5313 isconnected to one end of the capacitor coupling electrode 5316 via thelayers E to F. The other end of the capacitor coupling electrode 5316 isgrounded by an external electrode. And the other end of the strip lineelectrode 5313 is connected to an internal terminal 23 (refer to FIG. 1)on the antenna terminal side so as to form a notch filter structure.

An electrode to be the receiving terminal R x 3 of W-CDMA (refer toFIGS. 1 and 4) is connected to one end of the capacitor couplingelectrode 5315 The capacitor coupling electrode 5315 is connected to theresonator electrode 5304 via the layers C to E, and the resonatorelectrode 5304 is connected to the capacitor coupling electrode 5307 viathe layer C, and the capacitor coupling electrode 5307 is connected tothe resonator electrode 5305 via the layer C. In addition, the resonatorelectrode 5305 is connected to the capacitor coupling electrode 5308 viathe layer C, and the capacitor coupling electrode 5308 is connected tothe resonator electrode 5306 via the layer C, and capacitor couplingelectrode 5307 is connected to the electrode 5308 via the layer D. Theresonator electrode 5306 is connected to the capacitor electrode 5310via the layers C and D. And the capacitor coupling electrode 5310 isconnected to the internal terminal 23 (refer to FIG. 1) on the antennaterminal side so as to form a band-pass filter structure.

Moreover, the transmitting terminal T x 1 (GSM TX) is corresponding to afirst transmitting terminal of the present invention, the receivingterminal R x 1 (GSM RX) is corresponding to a first receiving terminalof the present invention, and the switching circuit (transmitting andreceiving switching circuit) 1 is corresponding to a first switchingcircuit of the present invention. In addition, the transmitting terminalT x 2 (DCS TX) is corresponding to a second transmitting terminal of thepresent invention and the receiving terminal R x 2 (DCS RX) iscorresponding to a second receiving terminal of the present inventionrespectively, and the internal terminal 23 is corresponding to a thirdinternal terminal of the present invention, and the switching circuit(transmitting and receiving switching circuit) 2 is corresponding to asecond switching circuit of the present invention. Moreover, theinternal terminal 21 to 22 are corresponding to the first and secondinternal terminals of the present invention respectively, the antennaterminal 20 is corresponding to the antenna terminal of the presentinvention, and the branching circuit 3 is corresponding to the branchingcircuit of the present invention. In addition, the transmitting terminalT x 3 (W-CDMA TX) is corresponding to a third transmitting terminal ofthe present invention, the receiving terminal R x 3 (W-CDMA RX) iscorresponding to a third receiving terminal of the present invention,and the duplexer 4 is corresponding to the duplexer of the presentinvention.

Thus, it is possible to support a system having the TDMA method and theW-CDMA method mixed therein by rendering an antenna switch on thehigh-frequency band (2 GHz band) side as the switching circuit 2 of 1input and 3 outputs (SP3T) and connecting the duplexer 4 thereto.Moreover, the internal terminal 23 (refer to FIG. 1) to have theduplexer 4 connected thereto is the terminal grounded via a diode D5(refer to FIG. 4), and so no diode exists on a signal route fortransmitting and receiving of W-CDMA and a low-loss characteristic maybe obtained.

The embodiment 1 was described in detail as above.

Moreover, while the first frequency band of the present invention wasthe one corresponding to the W-CDMA method in the above-mentionedembodiment, it is not limited thereto but may be any frequency band, inshort, as far as it is the one of performing simultaneous transmittingand receiving by utilizing the duplexer (for instance, it is possible tosupport the CDMA method of 800 MHz by connecting the switching circuits1 and 2 to the internal terminal 22 and 21 respectively and using theduplexer 4 (refer to FIG. 1)).

In addition, the third internal terminal of the present invention wasthe terminal grounded via the diode D5 (refer to FIG. 4) as well asconnected to the branching circuit 3 in this embodiment described above.However, not limiting thereto, but the third internal terminal of thepresent invention may be the terminal connected to the branching circuitvia the diode to be in the forward direction on transmitting andreceiving of the first frequency band as shown in FIG. 6 which is thecircuit diagram of the 3-frequency branching circuit wherein, forinstance, the internal terminal 23 (refer to FIG. 1) is connected to thebranching circuit 3 via the diode D1. In such a 3-frequency branchingcircuit, on transmitting and receiving of W-CDMA for instance, (a)although the signal loss increases a little because the diode D1 existson the signal route, (b) the occurrence of the signal distortion isreduced because only the diode D3 is the diode to be in the off state.

Moreover, as shown in FIG. 7 which is an explanatory view of the3-frequency branching circuit having a low-pass filter 11 insertedbetween the branching circuit 3 and a switching circuit 2 (moreover, theduplexer 4 (omitted in the drawing) is connected to the terminal R x 2or the terminal RX), the 3-frequency branching circuit of the presentinvention may have the low-pass filter inserted between the branchingcircuit and the second switching circuit. In such a 3-frequencybranching circuit, on transmitting and receiving of DCS for instance,the low-pass filter 11 (a) curbs the signal distortion occurring due toan amplifier (omitted in the drawing) in synergy with the low-passfilter 13, and (b) reduces the signal distortion occurring due to thediode D1 to be in the off state.

In addition, as shown in FIG. 8 which is an explanatory view of the3-frequency branching circuit having grounding resistor R shared betweenthe switching circuits 1 and 2 (moreover, the duplexer 4 (omitted in thedrawing) is connected to the terminal R x 2 or the terminal RX), the3-frequency branching circuit of the present invention may havegrounding resistor shared between the first switching circuit and thesecond switching circuit (in this case, resistors R1 to R3 (refer toFIG. 1) are unnecessary). In such a 3-frequency branching circuit, ontransmitting of GSM (DCS, W-CDMA) for instance, the diodes D1, D3 and D5(diodes D2 and D4) generates little signal distortion because a reversebias voltage is applied.

In short, the present invention is the branching circuit having thefilter function of passing the transmitting frequency band and thereceiving frequency band in each of the first to Nth frequency bands forinstance, and is equipped with the first and second internal terminals,the antenna terminal of connecting to the antenna, and the branchingcircuit having the first filter of passing the n+1-th (2≦n≦N−1) to Nthfrequency bands between the first internal terminal and the antennaterminal and the second filter of passing the first to nth frequencybands between the second internal terminal and the antenna terminal, thefirst switching circuit connected to the first internal terminal ofswitching between the transmitting frequency bands and the receivingfrequency bands of the n+1-th to Nth frequency bands, the secondswitching circuit connected to the second internal terminal of switchingbetween the transmitting frequency bands of the first frequency band andthe second to the nth frequency bands and the receiving frequency bandsof the second to the nth frequency bands, and the duplexer of branchingthe transmitting frequency band and the receiving frequency band of thefirst frequency band.

Moreover, the present invention is the above-mentioned 3-frequencybranching circuit characterized in that at least one of the abovedescribed plurality of switching circuits includes the diode, forinstance.

In addition, the present invention is the above-mentioned 3-frequencybranching circuit characterized in that, for instance, the abovedescribed first switching circuit has the first diode of which anode isconnected to the transmitting circuit side of the above-mentioned thirdfrequency band and cathode is connected to the above described branchingcircuit, the first strip line of which one end is connected to the anodeof the above described first diode and other end is grounded via thefirst capacitor and also connected to the first control terminal, thesecond diode of which anode is connected to the receiving circuit sideof the above-mentioned third frequency band and cathode is grounded viathe second capacitor and a parallel circuit of the first resistor, andthe second strip line of which one end is connected to the anode of theabove described second diode and other end is connected to the abovedescribed branching circuit, and the above described second switchingcircuit has the third diode of which anode is connected to thetransmitting circuit side of the above-mentioned second frequency bandand cathode is connected to the above described branching circuit side,the third strip line of which one end is connected to the anode of theabove described third diode and other end is grounded via the thirdcapacitor and also connected to the second control terminal, the fourthdiode of which anode is connected to the receiving circuit side of theabove-mentioned second frequency band and cathode is connected to theabove described branching circuit side, and the fourth strip line ofwhich one end is connected to the anode of the above described fourthdiode and other end is grounded via the fourth capacitor and connectedto the third control terminal, the fifth diode of which anode isconnected to the transmitting and receiving circuit side of the abovedescribed first frequency band and cathode is grounded via the fifthcapacitor and the parallel circuit of the second resistor, and the fifthstrip line of which one end is connected to the anode of the abovedescribed fifth diode and other end is connected to the above describedbranching circuit.

In addition, the present invention is the above-mentioned 3-frequencybranching circuit wherein the duplexer is connected to the third diodeportion, for instance.

Moreover, the present invention is the above-mentioned 3-frequencybranching circuit characterized by having at least one low-pass filterbetween a transmitting circuit terminal of the above described secondfrequency band and the antenna terminal, for instance.

In addition, the present invention is the above-mentioned 3-frequencybranching circuit characterized by having the configuration in which acoaxial type resonator is used for the above described duplexer, forinstance.

Moreover, the present invention is the above-mentioned 3-frequencybranching circuit characterized by having the configuration in which alayered filter using a dielectric green sheet is used for the abovedescribed duplexer, for instance.

In addition, as shown in FIGS. 9 (a) to (b), for instance, the presentinvention is the above-mentioned 3-frequency branching circuitcharacterized by having the configuration in which a SAW filter is usedfor the above described duplexer. Moreover, FIG. 9 (a) is an explanatoryview of the 3-frequency branching circuit (front) equipped with the SAWfilter and FIG. 9 (b) is an explanatory view of the same 3-frequencybranching circuit (backside), for instance.

Moreover, as to the above-mentioned, the duplexer may be constituted asa device different from other device (in this case, the third internalterminal of the present invention is the terminal of connecting theduplexer provided substantially outside the above described otherdevice).

In addition, the present invention is the above-mentioned 3-frequencybranching circuit characterized in that the above described duplexer iscomprised of the notch filter and band pass filter, and the signal ofthe transmitting frequency band is transmitted via the notch filter andthe signal of the receiving frequency band is transmitted via theband-pass filter, for instance.

Moreover, the present invention is the above-mentioned 3-frequencybranching circuit characterized in that the above described notch filteris comprised of the layered filter, and the above described band-passfilter is comprised of the coaxial type resonator, for instance.

In addition, the present invention is the above-mentioned 3-frequencybranching circuit characterized in that the above described notch filteris comprised of the layered filter, and the above described band-passfilter is comprised of the SAW filter, for instance.

Moreover, the present invention is the above-mentioned 3-frequencybranching circuit characterized in that the above described first filteris a low-pass filter of passing the low frequency band and the abovedescribed second filter is a high-pass filter of passing the highfrequency band, for instance.

In addition, the present invention is the above-mentioned 3-frequencybranching circuit characterized in that the above described first filteris the low-pass filter of passing the low frequency band and the abovedescribed second filter is the band pass filter of passing the highfrequency band, for instance.

Moreover, the present invention is the above-mentioned 3-frequencybranching circuit characterized in that the above described first filterand second filter are comprised of multilayered products using thedielectric green sheets, for instance.

In addition, the present invention is the above-mentioned 3-frequencybranching circuit characterized in that the above described firstswitching circuit and/or the second switching circuit are/is constitutedby mounting a switching element on the multilayered product using thedielectric green sheets, for instance.

Moreover, the present invention is the above-mentioned 3-frequencybranching circuit characterized in that the above described duplexer andmultilayered product are formed by dielectrics mutually having differentdielectric constants, for instance.

In addition, as shown in FIGS. 10 (a) to (b), the present invention isthe above-mentioned 3-frequency branching circuit characterized byhaving the configuration in which the above described duplexer ismounted on the multilayered product, for instance. Moreover, FIG. 10 (a)is an explanatory view of the 3-frequency branching circuit (front)equipped with a duplexer on a multilayered product and FIG. 10 (b) is anexplanatory view of the same 3-frequency branching circuit (backside),for instance.

Moreover, as shown in FIGS. 11 (a) to (b), the present invention is theabove-mentioned 3-frequency branching circuit characterized in that theabove described duplexer is formed inside the above describedmultilayered product, for instance. Incidentally, FIG. 11 (a) is anexplanatory view of the 3-frequency branching circuit (front) equippedwith the duplexer in the multilayered product and FIG. 11 (b) is anexplanatory view of the same 3-frequency branching circuit (backside).

In addition, the present invention is the above-mentioned 3-frequencybranching circuit characterized by having the configuration in which anFET switch is used for at least one of the above described first andsecond switching circuits, for instance.

Moreover, the present invention is the above-mentioned 3-frequencybranching circuit characterized by being a system method in which, ofthe above described plurality of frequency bands, the frequency bandpassing through the duplexer performs the simultaneous transmitting andreceiving, for instance.

In addition, the present invention is radio communication equipmentcharacterized by having an antenna of transmitting and receiving thesignal, the above-mentioned 3-frequency branching circuit of inputtingand outputting the above described transmitted and received signal, andsignal processing device which processes the signal branched by theabove-mentioned 3-frequency branching circuit, for instance.

Second Embodiment

Hereafter, the 3-frequency branching circuit according to a secondembodiment of the present invention will be described by referring toFIG. 12, while taking as a concrete example the circuit of the filter ofpassing the transmitting frequency bands and receiving frequency bandsof the three frequencies of the GSM and DCS methods used in the mobilecommunication in Europe and the W-CDMA method expected to be introducedin future. Moreover, FIG. 12 shows a circuit diagram of the 3-frequencybranching circuit according to the second embodiment.

In FIG. 12, a transmitting and receiving signal from an antenna terminal3101 as a common terminal of the transmitting and receiving of GSM, thetransmitting and receiving of W-CDMA and the transmitting and receivingof DCS are branched into the transmitting and receiving signal of GSM,the transmitting and receiving signal of W-CDMA and the transmitting andreceiving signal of DCS by a branching circuit 3102 comprised of thelow-pass filter and high-pass filter having a function of branching thelow frequency band and high frequency band.

The transmitting and receiving signal of GSM branched by the branchingcircuit 3102 is branched into the transmitting signal and receivingsignal of GSM by a first transmitting and receiving switching circuit104 from a first internal terminal 3103 (refer to FIG. 12 <1>) which isa transmitting and receiving terminal of GSM. The transmitting andreceiving signal of W-CDMA and the transmitting and receiving signal ofDCS branched by the branching circuit 3102 are branched into thetransmitting and receiving signal of W-CDMA and the transmitting andreceiving signal of DCS by a 2-frequencieswitching circuit 3106 from asecond internal terminal 3105 (refer to FIG. 12 <2>) which is a2-frequency common terminal.

The transmitting and receiving signal of DCS branched by the2-frequencieswitching circuit 3106 is branched into the transmittingsignal and receiving signal of DCS by a second transmitting andreceiving switching circuit 3108 from a third internal terminal 3107(refer to FIG. 12 <3>) which is the transmitting and receiving terminalof DCS. The transmitting and receiving signal of W-CDMA branched by the2-frequencieswitching circuit 3106 is branched into the transmittingsignal and receiving signal of W-CDMA by a duplexer 3110 from a fourthterminal 3109 (refer to FIG. 12 <4>) which is the transmitting andreceiving terminal of W-CDMA.

As described above, this embodiment allows simultaneous receiving of GSMand W-CDMA or DCS by performing the following around the antenna so asto implement the 3-frequency branching circuit including the W-CDMAmethod requiring the simultaneous transmitting and receiving. (1) To usethe branching circuit of branching the low frequency band and highfrequency band to branch the transmitting and receiving signal of GSMfrom the transmitting and receiving signal of W-CDMA and thetransmitting and receiving signal of DCS, (2) and branch thetransmitting and receiving signal of W-CDMA and the transmitting andreceiving signal of DCS on the 2-frequencieswitching circuit.Furthermore, the transmitting and receiving switching circuits 3104 and3108 do not pass a current for receiving of GSM and DCS, leading toreduction in current consumption.

Moreover, it has the configuration wherein two 2-frequencieswitchingcircuits (the 2-frequencieswitching circuit 3106 and the secondtransmitting and receiving switching circuit 3108) are passed throughbetween the second internal terminal 3105 and the third internalterminal 3107 which is the transmitting and receiving terminal of DCS,so that isolation between W-CDMA terminals (W-CDMA TX and W-CDMA RX) andDCS terminals (DCS TX and DCS RX) is improved and distortioncharacteristics to mutual transmitting signals are also improved.

Third Embodiment

Next, the configuration and operation of the 3-frequency branchingcircuit according to a third embodiment of the present invention will bedescribed. As the configuration and operation of the 3-frequencybranching circuit according to this embodiment are almost the same asthose in the above-mentioned first embodiment, the configuration andoperation of the multilayered product of the 3-frequency branchingcircuit will be described as a major difference by referring to FIGS. 13to 15. Moreover, FIG. 13 is a perspective view of the multilayeredproduct constituting the 3-frequency branching circuit according to thisembodiment, FIG. 14 is an exploded perspective view thereof, and FIG. 15is an equivalent circuit diagram thereof.

In FIG. 13, a multilayered product 3201 using the dielectric green sheetof the 3-frequency branching circuit is formed by a large number of thedielectric layers, and external electrodes 3202, 3203, 3204, 3205, 3206,3207, 3208, 3209, 3210 and 3211 are provided on and in the proximity ofthe sides of the multilayered product 3201.

In FIG. 14, the layer A has a first ground electrode 3301 formedtherein. In addition, the layer B has first, second, third, fourth andfifth resonator electrodes 3302, 3303, 3304, 3305 and 3306 formedtherein, and furthermore, the layer C has first and second capacitorcoupling electrodes 3307 and 3308 formed therein. Moreover, the layer Dhas third, fourth, fifth and sixth capacitor coupling electrodes 3309,3310, 3311, 3312 and first and second strip line electrodes 3313 and3314 formed therein. The layers E, F and G have seventh, eighth andninth capacitor coupling electrodes 3315, 3316 and 3317 formed therein.Furthermore, the layer H has a second ground electrode 3318 formedtherein.

An external electrode 3209 is the transmitting terminal of W-CDMA, andthe strip line electrode 3314 is connected thereto. Furthermore, acapacity is formed between the ground electrode 3318 and the externalelectrode 3209 to which the capacitor coupling electrode 3317 isconnected.

One end of the strip line electrode 3314 is connected to one end of thecapacitor coupling electrode 3312, and the capacitor coupling electrode3312 is connected to the resonator electrode 3302 via the layers C andD. The other end of the capacitor coupling electrode 3312 is connectedto one end of the capacitor coupling electrode 3311, and the capacitorcoupling electrode 3311 is connected to the resonator electrode 3303 viathe layers C and D.

The other end of the capacitor coupling electrode 3311 is connected toone end of the strip line electrode 3313, one end of the strip lineelectrode 3313 is connected to one end of the capacitor couplingelectrode 3316 via the layers E and F, and the other end of thecapacitor coupling electrode 3316 is connected to the ground by theexternal electrode 3207, and furthermore, the other end of the stripline electrode 3313 is connected to the external electrode 3202 (referto FIG. 13) which is a fourth terminal (refer to FIG. 12 <4>) so as toform the notch filter structure.

The external electrode 3205 (refer to FIG. 13) is the receiving terminalof W-CDMA, and is connected to one end of the capacitor couplingelectrode 3315. The capacitor coupling electrode 3315 is connected tothe resonator electrode 3304 via the layers C, D and E, and theresonator electrode 3304 is connected to the capacitor couplingelectrode 3307 via the layer C, and the capacitor coupling electrode3307 is connected to the resonator electrode 3305 via the layer C. Inaddition, the resonator electrode 3305 is connected to the capacitorcoupling electrode 3308 via the layer C, and the capacitor couplingelectrode 3308 is connected to the resonator electrode 3306 via thelayer C, and furthermore, the capacitor coupling electrode 3307 isconnected to the capacitor coupling electrode 3308 via the layer D.

The resonator electrode 3306 is connected to the capacitor couplingelectrode 3310 via the layers C and D, and the capacitor couplingelectrode 3310 is connected to the external electrode 3202 (refer toFIG. 13) which is the fourth terminal (refer to FIG. 12 <4>) so as toform the band-pass filter structure. Moreover, the external electrodes3203, 3204, 3206, 3207, 3208, 3210 and 3211 (refer to FIG. 13) form theground electrode.

As described above, according to this embodiment, it is possible toimplement a smaller size by using a layered type duplexer, and acoupling portion of the notch filter passing the transmitting frequencyband of W-CDMA can curb waves by two to three times more than thetransmitting frequency band of W-CDMA by implementing the low-passfilter structure of LC. As above, this embodiment was described indetail by taking the layered type duplexer as an example, but it is alsopossible to implement the smaller size by using the SAW (surfaceacoustic wave) filter as the duplexer.

Moreover, as shown in FIG. 16, it is possible, according to requirementcharacteristics, to reduce losses by using a combined configuration ofconstituting with the coaxial type resonator a notch filter 3501 passingthe transmitting frequency band of W-CDMA of the duplexer andconstituting with a multilayered product 3502 the band pass filterpassing the receiving frequency band of W-CDMA of the duplexer.

In addition, as shown in FIG. 17, it is possible, according to therequirement characteristics, to implement the smaller size by using thecombined configuration of constituting with the coaxial type resonator anotch filter 3601 passing the transmitting frequency band of W-CDMA ofthe duplexer and constituting with a surface acoustic wave filter 3602the band pass filter passing the receiving frequency band of W-CDMA ofthe duplexer.

Furthermore, as shown in FIG. 18, it is possible, according to therequirement characteristics, to implement the smaller size by using thecombined configuration of constituting with the multilayered product anotch filter 3701 passing the transmitting frequency band of W-CDMA ofthe duplexer and constituting with a surface acoustic wave filter 3702the band pass filter passing the receiving frequency band of W-CDMA ofthe duplexer.

Fourth Embodiment

Next, the configuration and operation of the 3-frequency branchingcircuit according to a fourth embodiment of the present invention willbe described. As the configuration and operation of the 3-frequencybranching circuit according to the fourth embodiment of the presentinvention are almost the same as those in the above-mentioned firstembodiment, the following will be described as the major differencestherefrom by referring to FIG. 19. (1) A branching filter of branchingthe low frequency band in the transmitting and receiving frequency bandof GSM and the high frequency band in the transmitting and receivingfrequency band of W-CDMA and DCS, (2) the switching circuit of switchingamong the transmitting and receiving frequency bands of W-CDMA, DCS andGSM, (3) the switching circuit of switching between the transmittingfrequency band of DCS and the receiving frequency band of DCS, and (4) aconnection terminal of the duplexer of switching between thetransmitting frequency band of W-CDMA and the receiving frequency bandof W-CDMA. Moreover, FIG. 19 is an equivalent circuit diagram of the3-frequency branching circuit according to this embodiment.

In FIG. 19, reference numeral 3801 denotes a first branching circuit,3802 denotes a first transmitting and receiving switching circuit, 3803denotes the 2-frequencieswitching circuit, 3804 denotes a secondtransmitting and receiving switching circuit, and 3805 denotes theduplexer. A first strip line L801, a second strip line L802 and a firstcapacitor C801 in FIG. 19 form the low-pass filter of passing a lowfrequency as shown by a waveform 1 in the example of a branching circuitcharacteristic shown in FIG. 20, and the second strip line L802 andfirst capacitor C801 are serially connected to the ground side so as toform an attenuation pole point A (refer to FIG. 20).

In addition, a second capacitor C802, a third strip line L803 and athird capacitor C803 in FIG. 19 form the high-pass filter of passing ahigh frequency as shown by a waveform 2 in FIG. 20, and the third stripline L803 and third capacitor C803 are serially connected to the groundside so as to form an attenuation pole point B (refer to FIG. 20).

A connection is made via such low-pass filter and high-pass filter to anantenna terminal 3806 which is the common terminal of the transmittingand receiving signal of GSM, the transmitting and receiving signal ofW-CDMA and the transmitting and receiving signal of DCS so that, whentransmitting or receiving a low frequenciesignal such as thetransmitting and receiving signal of GSM, isolation is well provided tothe low frequenciesignal by the attenuation pole B on the high-passfilter side from a contact A (refer to FIG. 19) and the signal will notbe leaked to the high-pass filter side.

Moreover, when transmitting or receiving a high frequenciesignal such asthe transmitting and receiving signals of W-CDMA and those of DCS, theisolation is well provided to the high frequenciesignal by theattenuation pole A on the low-pass filter side from the contact A (referto FIG. 19) and the signal will not be leaked to the low-pass filterside. To be more specific, the branching circuit 3801 provides thefunction of branching the low frequenciesignal such as the transmittingand receiving signal of GSM and the high frequenciesignal such as thetransmitting and receiving signal of W-CDMA and that of DCS. Inaddition, the contact A (refer to FIG. 19) is connected to the antennaterminal 3806 via a fourth capacitor C804. The transmitting andreceiving signal of GSM branched by the branching circuit 3801 istransmitted via a contact B (refer to FIG. 19) of the first transmittingand receiving switching circuit.

A transmitting circuit side terminal 3807 of GSM in the firsttransmitting and receiving switching circuit 3802 is connected to theanode of a first diode P801 via a fifth capacitor C805, and the cathodeof the diode P801 is connected to the contact B. Furthermore, one end ofa fourth strip line L804 is connected between the anode of the firstdiode P801 and the fifth capacitor C805, and the other end of the fourthstrip line L804 is connected to a first control terminal 3808.

The other end of the fourth strip line L804 is further connected to theground via a sixth capacitor C806, and the first control terminal 3808plays a role of switching the transmitting and receiving signal of oneof transmitting and receiving change-over switches of GSM. In addition,the first diode P801 has a fifth strip line L805 and a series circuit ofa seventh capacitor C807 connected in parallel thereto.

A receiving circuit side terminal 3809 of GSM in the first transmittingand receiving switching circuit 3802 is connected to the anode of asecond diode P802 via an eighth capacitor C808. The cathode of thesecond diode P802 is connected to the ground via a resistor R801 and aparallel circuit of a ninth capacitor C809. The anode of the seconddiode P802 is further connected to one end of a sixth strip line L806,and the other end of the sixth strip line L806 is connected to thecontact B (refer to FIG. 19). The transmitting and receiving signals ofW-CDMA and DCS branched by the branching circuit 3801 are transmittedvia a contact C (refer to FIG. 19) of the first transmitting andreceiving switching circuit.

A fourth terminal 3810 on the W-CDMA side of the 2-frequencieswitchingcircuit 3803 is connected to the anode of a third diode P803 via a tenthcapacitor C810, and the cathode of the third diode P803 is connected tothe contact C. Furthermore, one end of a seventh strip line L807 isconnected between the anode of the third diode P803 and the tenthcapacitor C810, and the other end of the seventh strip line L807 isconnected to a second control terminal 3811.

The other end of the seventh strip line L807 is further connected to theground via an eleventh capacitor C811, and the second control terminal3811 plays a role of switching between the W-CDMA transmitting andreceiving signal and the DCS transmitting and receiving signal. Inaddition, the third diode P803 further has an eighth strip line L808 anda series circuit of a twelfth capacitor C812 connected in parallelthereto. Moreover, the internal terminal 3810 is connected to theduplexer 3805, and the duplexer 3805 is connected to a W-CDMAtransmitting side terminal 3812 and a receiving side terminal 3813.

An internal terminal 3814 on the DCS side in the 2-frequencieswitchingcircuit 3803 is connected to the anode of a fourth diode P804 via athirteenth capacitor C813, and the cathode of the fourth diode P804 isconnected to the ground via a resistor R802 and the parallel circuit ofa fourteenth capacitor C814. In addition, the anode of the fourth diodeP804 is further connected to one end of a ninth strip line L809, and theother end of the ninth strip line L809 is connected to the contact C(refer to FIG. 19). The transmitting and receiving signal of DCSbranched by the 2-frequencieswitching circuit 3803 is transmitted via acontact D (refer to FIG. 19) of the second transmitting and receivingswitching circuit.

A transmitting circuit side terminal 3815 of DCS of the secondtransmitting and receiving switching circuit 3804 is connected to theanode of a fifth diode P805 via a fifteenth capacitor C815, and thecathode of the fifth diode P805 is connected to the contact D.Furthermore, one end of a tenth strip line L810 is connected between theanode of the fifth diode P805 and the fifteenth capacitor C815, and theother end of the tenth strip line L810 is connected to a third controlterminal 3816. The other end of the tenth strip line L810 is furtherconnected to the ground via a sixteenth capacitor C816, and the thirdcontrol terminal 3816 plays a role of switching between the transmittingand receiving of the DCS. In addition, the fifth diode P805 further hasan eleventh strip line L811 and the series circuit of a seventeenthcapacitor C817 connected in parallel thereto.

A receiving circuit side terminal 3817 of DCS in the second transmittingand receiving switching circuit 3804 is connected to the anode of asixth diode P806 via an eighteenth capacitor C818. The cathode of thesixth diode P806 is connected to the ground via a resistor R803 and aparallel circuit of a nineteenth capacitor C819. The anode of the sixthdiode P806 is further connected to one end of a twelfth strip line L812,and the other end of the twelfth strip line L812 is connected to thecontact D (refer to FIG. 19).

The transmitting and receiving signal of W-CDMA branched by the2-frequency branching circuit 3803 is transmitted to the duplexer 3805via the internal terminal 3810 on the W-CDMA side. As a configuration ofthe duplexer, it is possible to render the 3-frequency branching circuitsmaller-size and reduce the losses by implementing the configurationshown in the second embodiment.

Moreover, the same results can be obtained by adding inductance elementsinstead of the resistors R801, R802 and R803 and putting the resistorsR801, R802 and R803 between the fourth strip line L804 and the firstcontrol terminal 3808, between the seventh strip line L807 and thesecond control terminal 3811, and between the tenth strip line L810 andthe third control terminal 3816 respectively.

In the case of transmitting by GSM, the first diode P801 and seconddiode P802 will be in the on state by applying a positive voltage to thefirst control terminal 3808. At this time, the capacitors C804, C805,C806 and C808 cut a DC component, and so the current does not run toeach terminal. A current value can be controlled by rendering theresistor R801 variable, and the signal transmitted from a transmittingterminal 3807 is not transmitted to the receiving side because impedanceof the sixth strip line L806 becomes an infinite size due to the seconddiode P802 connected to the ground side.

Moreover, as the inductance component of the second diode P802 resonateswith the capacitor C809, it is possible to render the impedance infinitewhen seeing the receiving side from the contact B at the transmittingfrequency of the transmitting signal, and the transmitting signal istransmitted to the antenna terminal 3806 through the low-pass filter ofthe branching circuit 3801.

Next, on receiving, the first diode P801 and second diode P802 are inthe off state because no voltage is applied to the first controlterminal 3808 so that the signal is transmitted to the receiving side ofGSM. At this time, as there is a capacitance component of the firstdiode P801, the receiving signal is not always transmitted from theantenna to the receiving terminal 3809, and so the capacitance componentof the first diode P801 is resonated with the fifth strip line L805. Itis thereby possible to take the isolation of the transmitting terminal3807 satisfactorily from the contact A at the receiving frequency of thereceiving signal so that the receiving signal can be transmitted fromthe antenna terminal 3806 to the receiving terminal 3809 of GSM via thelow-pass filter.

Next, the cases of branching the transmitting and receiving signal ofW-CDMA or that of DCS will be described. The third diode P803 and thefourth diode P804 will be in the on state by applying the positivevoltage to the second control terminal 3811. At this time, thecapacitors C810, C811, C812 and C813 cut the DC component, and so thecurrent does not run to each terminal.

A current value can be controlled by rendering the resistor R802variable, and the signal transmitted and received from the fourthterminal 3810 on the W-CDMA side is not transmitted to the DCS sidebecause impedance of the ninth strip line L809 becomes infinite due tothe fourth diode P804 connected to the ground side.

At this time, the inductance component of the fourth diode P804resonates with the capacitor C814, it is possible to render theimpedance infinite when seeing the DCS side from the contact C at thefrequency of W-CDMA, and the transmitting and receiving signal of W-CDMAis transmitted to the antenna terminal 3806 through the high-pass filterof the branching circuit 3801. The internal terminal 3810 on the W-CDMAside is connected to the duplexer 3805, and the duplexer 3805 isconnected to the transmitting side terminal 3812 and the receiving sideterminal 3813 of W-CDMA, allowing the simultaneous transmitting andreceiving by W-CDMA.

In addition, on operation of DCS, no voltage is applied to the secondcontrol terminal 3811 so that the third diode P803 and the fourth diodeP804 are in the off state, and the transmitting and receiving signal ofDCS is transmitted to the antenna terminal 3806 via the high-pass filterof the branching circuit 3801. At this time, as there is the capacitancecomponent of the third diode P803, the transmitting and receiving signalof DCS is not always transmitted to the antenna terminal 3806, and sothe capacitance component of the third diode P803 is resonated with theeighth strip line L808. It is thereby possible to take the isolation ofthe internal terminal 3810 on the W-CDMA side satisfactorily from thecontact C against the receiving frequency of the transmitting andreceiving signal of DCS so that the transmitting and receiving signal ofDCS can be efficiently transmitted from the antenna terminal 3806 viathe high-pass filter of the branching circuit 3801.

In the case of transmitting by DCS, the fifth diode P805 and sixth diodeP806 will be in the on state by applying the positive voltage to thethird control terminal 3814. At this time, the capacitors C815, C816,C817 and C818 cut the DC component, and so the current does not run toeach terminal. The current value can be controlled by rendering theresistor R803 variable, and the signal transmitted from the transmittingterminal 3815 is not transmitted to the receiving side because theimpedance of the twelfth strip line L812 becomes infinite due to thesixth diode P806 connected to the ground side. Moreover, as theinductance component of the sixth diode P806 resonates with thecapacitor C819, it is possible to render the impedance infinite whenseeing the receiving side from the contact D at the transmittingfrequency of the transmitting signal, and the transmitting signal istransmitted to the antenna terminal 3806 through the2-frequencieswitching circuit 3803 and the high-pass filters of thebranching circuit 3801.

Next, on receiving, the fifth diode P805 and sixth diode P806 are in theoff state because no voltage is applied to the third control terminal3816 so that the signal is transmitted to the receiving side of DCS.

At this time, as there is a capacitance component of the fifth diodeP805, the receiving signal is not always transmitted from the antenna tothe receiving terminal 3816, and so the capacitance component of thefifth diode P805 is resonated with the eleventh strip line L811. It isthereby possible to take the isolation of the transmitting terminal 3815satisfactorily from the contact D at the receiving frequency of thereceiving signal so that the receiving signal can be transmitted fromthe antenna terminal 3806 to the receiving terminal 3809 of DCS via thehigh-pass filter of the branching circuit 3801 and the2-frequencieswitching circuit 3803.

Moreover, in the case of transmitting and receiving by DCS, no voltageis applied to the second control terminal 3811 as previously mentioned.

As described above, as for the transmitting and receiving signal of GSM,the transmitting and receiving signal of W-CDMA and the transmitting andreceiving signal of DCS, this embodiment allows the simultaneousreceiving of GSM and W-CDMA or DCS and also the simultaneoustransmitting and receiving of W-CDMA by providing the branching circuitcomprised of the low-pass filter of passing the low frequency and thehigh-pass filter of passing the high frequency immediately below theantenna terminal and placing the 2-frequencieswitching circuit on theterminal on the high frequencieside, and after the branching, theduplexer on the W-CDMA side, and the transmitting and receivingswitching circuit on the DCS side.

In addition, it is possible to eliminate undesired signals by two orthree times of the waves of the transmitting frequency bands of theW-CDMA and DCS by using the band pass filter for the high-pass filterportion of the branching circuit 3801.

Moreover, the 3-frequency branching circuit may have the configurationas shown in FIG. 21. The difference from FIG. 19 is that the2-frequencieswitching circuit 3803 is directly connected with the secondtransmitting and receiving switching circuit 3804 not via the thirteenthcapacitor C813. In this case, when transmitting W-CDMA, the positivevoltage is applied to the second control terminal 3811 and the reversebias voltage is provided to the fifth diode P805 without cutting adirect current, so that the distortion generated by applying high powerto the fifth diode P805 when it is off is improved. In addition, whentransmitting DCS, the positive voltage is applied to the third controlterminal 3814 and the reverse bias voltage is provided to the thirddiode P803 without cutting the direct current, so that the distortiongenerated by applying the high power to the third diode P803 when it isoff is improved.

Moreover, as for this configuration, the same effect can be obtained, asshown in FIG. 22, by connecting the contact C to the contact D via astrip line 4101. In this case, the strip line 4101 has the function, asa choke coil, of blocking leaking of the signal of the frequency on theW-CDMA side to the DCS side.

Fifth Embodiment

Next, the configuration of the 3-frequency branching circuit accordingto a fifth embodiment of the present invention will be described. FIG.23 is a perspective view of the configuration of the 3-frequencybranching circuit. In FIG. 23, it has the configuration wherein a secondmultilayered product 4202 is placed on a first multilayered product4201. In addition, first to sixth pin diodes P801, P802, P803, P804,P805 and P806 and the first to third resistors R801, R802 and R803 areplaced on the top face of the first multilayered product. Moreover, thediodes may be welding-packaged, bare chip-packaged or flipchip-packaged, and the resistor may be a printed resistor.

The first multilayered product 4201 is formed by a large number ofdielectric layers, and internal layers have a circuit configurationincluding a branching circuit 4801, first and second transmitting andreceiving switching circuits 4802 and 4804 and a 2-frequencieswitchingcircuit 4803. In addition, the first multilayered product 4201 also hasthe function of a laminated substrate, and a plurality of terminalelectrodes 4203 are formed around it. The terminal electrodes 4203 areconnected to the respective circuits formed in the internal layers.Moreover, the terminal electrodes 4203 are the ground electrodes,control terminals and transmitting and receiving terminals of variousmethods, and are appropriately placed by external circuit configuration.

It is preferable to use the dielectric of which specific inductivecapacity is 10 or less for the dielectric of the first multilayeredproduct 4201, and it may have the configuration wherein a crystal phaseincludes at least one of AL₂O₃, MgO, SiO₂ and ROa (R is at least oneelement selected from La, Ce, Pr, Nd, Sm and Gd, and a is a numericalvalue stoichiometrically determined according to the value of the abovedescribed R). The second multilayered product 4202 is formed by a largenumber of dielectric layers, and the duplexer is formed in the internallayer. It is preferable to use the dielectric of which specificinductive capacity is comparatively large for the dielectric of thesecond multilayered product 4202, and it may be have the configurationwherein main components are Bi₂O₃, and Nb₂O₅. In addition, the terminalelectrodes 4203 can have the same effect if formed not around it but onthe bottom face of it.

In addition, while the second multilayered product 4202 is placed on atop surface of the first multilayered product 4201 in this embodiment,it may also be the placement configuration wherein the firstmultilayered product 4201 and the second multilayered product 4202 areseparated and arranged sideways on a substrate 4301 as shown in FIG. 24.In this case, the circuit configuration in the internal layer of thefirst multilayered product 4201 is formed with an allowance to allow theisolation among the elements to be enhanced by increasing the groundelectrodes for instance and also to allow height of the secondmultilayered product 4202 to be higher, and so the thickness of theresonator in the internal layer can be increased so as to further reducethe losses.

In addition, on the top surface of the first multilayered product 4201it is possible to have an inductor (or the strip line) and the capacitorin the internal layers of the first multilayered product 4201 mounted asdiscrete parts. These are placed as appropriate according to thecharacteristics of the 3-frequency branching circuit. In addition,placement of other parts is not limited thereto but they are placed asappropriate according to an internal layer pattern and a terminalposition. As described above, in this embodiment, it is possible toimplement the smaller size by having the transmitting and receivingswitching circuits, 2-frequencieswitching circuits and duplexer formedby the multilayered products.

Moreover, while this embodiment was described in detail by taking thelayered type duplexer as an example, it is also possible to implementthe smaller size by using the SAW filter utilizing the surface acousticwave as the duplexer. In addition, it is also possible, according to therequirement characteristics, to implement it by combining the coaxialtype, layered type and SAW filter.

The above description was made on the second to fifth embodiments of thepresent invention in detail.

Moreover, the branching circuit of the present invention was the3-frequency branching circuit exemplified by the GSM, W-CDMA and DCS inthe above-mentioned second to fifth embodiments. However, not limitingthereto, the branching circuit of the present invention is, in short,the branching circuit having the filter function of passing thetransmitting frequency band and receiving frequency band in each of thefirst to Nth frequency bands, and is equipped with the first, second,third and fourth internal terminals, the antenna terminal of connectingto the antenna, and the branching circuit having the first filter ofpassing the n+1-th (2≦n≦N−1) to Nth frequency bands between the firstinternal terminal and the antenna terminal and the second filter ofpassing the first to nth frequency bands between the second internalterminal and the antenna terminal, the first switching circuit connectedto the first internal terminal of switching among the n+1-th to Nthfrequency bands, the second switching circuit connected to the secondinternal terminal of switching the second to the nth frequency bands tothe third internal terminal and switching the first frequency band tothe fourth internal terminal for transmission, the third switchingcircuit connected to the third internal terminal of switching among thesecond to the nth frequency bands, and the duplexer connected to thefourth internal terminal of branching the transmitting frequency bandand the receiving frequency band of the first frequency band (inaddition, the branching circuit of the present invention may be the onehaving interchanged the roles of the input and output in such abranching circuit).

In addition, mobile communication equipment of the present invention ischaracterized by having the antenna of transmitting and receiving thesignal, the branching circuit of the present invention (3-frequencybranching circuit) of inputting and outputting the transmitted andreceived signal, and the signal processing device which processes thesignal branched by the branching circuit (3-frequency branchingcircuit), and it is applicable, by using the 3-frequency branchingcircuit of the present invention, to the mobile communication equipmentof the W-CDMA method or the like requiring the simultaneous transmittingand receiving.

Thus, according to the present invention, for instance, it allows thesimultaneous receiving of GSM and W-CDMA or DCS by using the branchingcircuit of branching the low frequency band and high frequency bandaround the antenna portion to branch the GSM transmitting and receivingsignal from the W-CDMA and DCS transmitting and receiving signals firstand using the 2-frequencieswitching circuit to branch the W-CDMAtransmitting and receiving signal from the DCS transmitting andreceiving signal, and it also allows the simultaneous transmitting andreceiving of W-CDMA by branching the transmitting and receivingfrequencies of the W-CDMA transmitting and receiving signals with theduplexer.

In addition, it is possible, according to the requirementcharacteristics, to implement the 3-frequency branching circuit of thesmaller size and reduced losses by using in the duplexer portion thecoaxial type duplexer using the coaxial type resonator if reduction inlosses is required, the duplexer of the layered type or using the SAWfilter if the smaller size is required, and further combining them, andit is feasible to provide the 3-frequency branching circuit, branchingcircuit and radio communication equipment also usable for the systemwherein the TDMA method and the W-CDMA method assuring high tone qualityand high speed data communication for instance are mixed.

Sixth Embodiment

Hereafter, the 3-frequency branching circuit according to a sixthembodiment of the present invention will be described by referring toFIG. 25, while taking as a concrete example the circuit of the filter ofpassing the transmitting frequency bands and receiving frequency bandsof the three frequencies of the GSM and DCS methods used in the mobilecommunication in Europe and the W-CDMA method expected to be introducedin future. Moreover, FIG. 25 shows a circuit diagram of the 3-frequencybranching circuit according to the sixth embodiment.

In FIG. 25, reference numeral 101 denotes the duplexer of which bandwidths are broad bands such as 880 to 960 MHz as the transmitting andreceiving frequency band of GSM, 1710 to 1980 MHz as the transmittingfrequency band of W-CDMA and the transmitting and receiving frequencyband of DCS and 2110 to 2170 MHz as the receiving frequency band ofW-CDMA, and having the function of branching narrow bands among thebands.

880 to 960 MHz as the transmitting and receiving frequency band of GSMand 1710 to 1980 MHz as the transmitting frequency band of W-CDMA andthe transmitting and receiving frequency band of DCS are branched firstfrom an antenna terminal 102 to a first internal terminal 103 which isthe common terminal of the transmitting and receiving of GSM, thetransmitting of W-CDMA and the transmitting and receiving of DCS or to asecond internal terminal 104 which is the receiving terminal of W-CDMA.

The transmitting and receiving signals from the first internal terminal103 which is the common terminal of the transmitting and receiving ofGSM, the transmitting of W-CDMA and the transmitting and receiving ofDCS are branched by a branching circuit 105 comprised of the low-passfilter and high-pass filter having the function of branching the lowfrequency band and high frequency band so that the transmitting andreceiving signal of GSM is branched to a transmitting and receivingswitching circuit (hereafter, also referred to as the first transmittingand receiving change-over switch) 106 side and the transmitting signalof W-CDMA and the transmitting and receiving signal of DCS are branchedto a transmitting and receiving switching circuit (hereafter, alsoreferred to as the second transmitting and receiving change-over switch)107 side respectively.

The transmitting and receiving signal of GSM branched by the branchingcircuit is branched into the transmitting signal and receiving signal ofGSM by the first transmitting and receiving switching circuit 106.

In addition, the transmitting signal of W-CDMA and the transmitting andreceiving signal of DCS branched by the branching circuit is branchedinto the transmitting signal of W-CDMA and the transmitting signal ofDCS and receiving signal of DCS by the second transmitting and receivingswitching circuit 107.

As described above, this embodiment allows the simultaneous receiving ofW-CDMA, GSM and DCS by using the duplexer around the antenna portion soas to (1) branch the W-CDMA receiving signal first and (2) branch theGSM transmitting and receiving signal from the W-CDMA transmittingsignal and the DCS transmitting and receiving signal by using thebranching circuit of branching the low frequency band and high frequencyband.

Furthermore, the transmitting and receiving switching circuits 106 and107 do not pass a current on receiving of GSM and DCS not to mentionreceiving of W-CDMA, leading to reduction in current consumption, and inaddition, it also has the effect of rendering the circuit scale smaller,implementing the smaller size and reducing insertion losses bysimultaneously performing the transmitting of W-CDMA and thetransmitting of DCS.

Moreover, in the case of taking the circuit configuration describedabove, the receiving signal of W-CDMA is branched first by the duplexeraround the antenna portion and so the receiving signal of W-CDMA can bereceived in a low-loss state so that high tone quality is assured forinstance.

Seventh Embodiment

Next, the configuration and operation of the 3-frequency branchingcircuit according to a seventh embodiment of the present invention willbe described. As the configuration and operation of the 3-frequencybranching circuit according to this embodiment are almost the same asthose in the above-mentioned sixth embodiment, the configuration andoperation of the coaxial type duplexer of the 3-frequency branchingcircuit as the major differences will be described by referring to FIGS.26 to 28. Moreover, FIG. 26 is an equivalent circuit diagram of thecoaxial type duplexer, FIG. 27 is a top view of thereof, and FIG. 28 isa characteristic view thereof.

In FIG. 26, a common terminal 201 for the transmitting and receiving ofGSM, the transmitting of W-CDMA and the transmitting and receiving ofDCS is connected to a first capacitor C201 connected to the ground and afirst inductor L201.

The other end of the first inductor L201 is connected to a coaxial typeresonator Res 201 via a second capacitor C202. In addition, a thirdcapacitor C203 is connected to the ground and further a second inductorL202 is connected thereto.

The other end of the second inductor L202 is connected to a coaxial typeresonator Res 202 via a fourth capacitor C204, and a fifth capacitorC205 connected to the ground and a third inductor L203 are furtherconnected thereto.

The other end of the third inductor L203 is connected to an antennaterminal 202 connected to the antenna.

A receiving terminal 203 of W-CDMA is connected to a sixth capacitorC206, and the other end of the sixth capacitor C206 is connected to acoaxial type resonator Res 203 in parallel, and to a seventh capacitorC207 and further to an eighth capacitor C208.

The other end of the eighth capacitor C208 is connected to a coaxialtype resonator Res 204 in parallel, and to a ninth capacitor C209.

The other end of the ninth capacitor C209 is connected to a coaxial typeresonator Res 205 in parallel, and to the other end of the seventhcapacitor C207 and further to a tenth capacitor C210, and to the antennaterminal 202.

The coaxial type duplexer comprised of such equivalent circuits will bedescribed further by referring to FIG. 27.

In FIG. 27, a wiring substrate P301 is made of a resin such as glassepoxy. In addition, the coaxial type resonator Res 201 to 205 are madeof dielectrics and so on, and are mounted on the wiring substrate P301by soldering together with the inductor elements such as an air corecoil and a chip capacitor.

The substrate P301 has external electrodes 301, 302, 303, 304, 305, 306,307, 308, 309 and 310 provided thereon. Moreover, the external electrode301 is the common terminal of the transmitting and receiving of GSM, thetransmitting of W-CDMA and the transmitting and receiving of DCS, theexternal electrode 309 is the antenna terminal, the external electrode307 is the receiving terminal of W-CDMA, and the external electrodes302, 303, 304, 305, 306, 308 and 310 have the ground terminals placedthereon.

Next, the characteristics of the duplexer will be described by referringto FIG. 28.

In FIG. 28, a waveform 1 is a waveform diagram of the transmitting andreceiving signal of GSM, the transmitting signal of W-CDMA and thetransmitting and receiving signal of DCS.

In the waveform 1, the transmitting and receiving frequency band of GSM,the transmitting frequency band of W-CDMA and the transmitting andreceiving frequency band of DCS are passed by using the notch filter.Moreover, selectivity is improved by attenuating the receiving frequencyband of W-CDMA.

A waveform 2 is a waveform diagram of the receiving signal of W-CDMA. Inthe waveform 2, the receiving frequency band of W-CDMA is passed byusing the band pass filter. Moreover, selectivity is improved byattenuating the transmitting and receiving frequency band of GSM, thetransmitting frequency band of W-CDMA and the transmitting and receivingfrequency band of DCS.

As described above, it is possible, according to this embodiment, toreduce the insertion losses of the transmitting and receiving signal ofGSM, the transmitting signal of W-CDMA, the transmitting and receivingsignal of DCS and the receiving signal of W-CDMA by using the coaxialtype duplexer. And the coupling portion of the notch filter passing thetransmitting and receiving band of GSM, the transmitting frequency bandof W-CDMA and the transmitting and receiving band of DCS has theconfiguration of the low-pass filter of LC so that it can curb waves bytwo to three times more than the transmitting frequency band of DCS orW-CDMA.

Eighth Embodiment

Next, the configuration and operation of the 3-frequency branchingcircuit according to an eighth embodiment of the present invention willbe described. As the configuration and operation of the 3-frequencybranching circuit according to this embodiment are almost the same asthose in the above-mentioned sixth embodiment, the configuration andoperation of the multilayered product of the 3-frequency branchingcircuit as the major differences will be described by referring to FIGS.29 to 31. Moreover, FIG. 29 is a perspective view of the multilayeredproduct constituting the 3-frequency branching circuit according to thisembodiment, FIG. 30 is an exploded perspective view thereof, and FIG. 31is an equivalent circuit diagram thereof.

In FIG. 29, a multilayered product 501 using the dielectric green sheetof the 3-frequency branching circuit is formed by a large number ofdielectric layers, and external electrodes 502, 503, 504, 505, 506, 507,508, 509, 510 and 511 are provided on and in the proximity of the sideof the multilayered product 501.

In FIG. 30, the layer A has a first ground electrode 601 formed thereon.In addition, the layer B has first, second, third, fourth and fifthresonator electrodes 602, 603, 604, 605 and 606 formed thereon, and thelayer C has first and second capacitor coupling electrodes 607 and 608formed thereon.

In addition, the layer D has third, fourth, fifth and sixth capacitorcoupling electrodes 609, 610, 611 and 612 and first and second stripline electrodes 613 and 614 formed thereon.

The layers E, F and G have seventh, eighth and ninth capacitor couplingelectrodes 615, 616 and 617 formed thereon. Furthermore, the layer H hasa second ground electrode 618 formed thereon.

The external electrode 509 is the common terminal of the transmittingand receiving of GSM, the transmitting of W-CDMA and the transmittingand receiving of DCS, and is connected to the strip line electrode 614.Furthermore, the external electrode 509 has the capacitor couplingelectrode 617 connected to the ground by the ground electrode 618.

One end of the strip line electrode 614 is connected to one end of thecapacitor coupling electrode 612, and the capacitor coupling electrode612 is connected to the resonator electrodes 602 via the layers C and D.

The other end of the capacitor coupling electrode 612 is connected toone end of the capacitor coupling electrode 611, and the capacitorcoupling electrode 611 is connected to the resonator electrode 603 viathe layers C and D.

The other end of the capacitor coupling electrode 611 is connected toone end of the strip line electrode 613, the one end of the strip lineelectrode 613 is connected to one end of the capacitor couplingelectrode 616 via the layers E and F, and the other end of the capacitorcoupling electrode 616 is connected to the ground by the externalelectrode 507, and furthermore, the other end of the strip lineelectrode 613 is connected to the external electrode 502 which is theantenna terminal so as to form the notch filter structure.

The external electrode 505 (refer to FIG. 29) is the receiving terminalof W-CDMA, and is connected to one end of the capacitor couplingelectrode 615.

The capacitor coupling electrode 615 has the resonator electrode 604connected thereto via the layers C, D and E, and the resonator electrode604 has the capacitor coupling electrode 607 connected thereto via thelayer C, and the capacitor coupling electrode 607 has the resonatorelectrode 605 connected thereto via the layer C. In addition, theresonator electrode 605 has the capacitor coupling electrode 608connected thereto via the layer C, and the capacitor coupling electrode608 has the resonator electrode 606 connected thereto via the layer C,and furthermore, the capacitor coupling electrode 607 has the capacitorcoupling electrode 608 connected thereto via the layer D.

The resonator electrode 606 has the capacitor coupling electrode 610connected thereto via the layers C and D, and the capacitor couplingelectrode 610 is connected to the external electrode 502 (refer to FIG.29) which is the antenna terminal so as to form the band pass filterstructure. Moreover, the external electrodes 503, 504, 506, 507, 508,510 and 511 (refer to FIG. 29) form the ground electrode.

As described above, according to this embodiment, it is possible toimplement the smaller size by using the layered type duplexer, and it isalso possible to curb the waves by two to three times more than thetransmitting frequency bands of DCS and W-CDMA for instance byimplementing the low-pass filter structure of LC with the couplingportion of the notch filter passing the transmitting and receivingfrequency band of GSM, the transmitting frequency band of W-CDMA and thetransmitting and receiving frequency band of DCS.

As above, this embodiment was described in detail by taking the layeredtype duplexer as an example, but it is also possible to implement thesmaller size by using the SAW filter utilizing the surface acoustic waveas the duplexer.

Moreover, as shown in FIG. 32, it is possible, according to therequirement characteristics, to implement the smaller size by using acombination of a notch filter 801 passing the transmitting and receivingfrequency band of GSM, the transmitting frequency band of W-CDMA and thetransmitting and receiving frequency band of DCS of the coaxial typeduplexer and a band pass filter 802 passing the receiving frequency bandof W-CDMA of the layered type duplexer.

In addition, as shown in FIG. 33, it is possible, according to therequirement characteristics, to implement the smaller size by using acoaxial type notch filter 901 passing the transmitting and receivingfrequency band of GSM, the transmitting frequency band of W-CDMA and thetransmitting and receiving frequency band of DCS of the coaxial typeduplexer and using a SAW filter 902 utilizing a surface acoustic wave asthe band pass filter passing the receiving frequency band of W-CDMA.

Furthermore, as shown in FIG. 34, it is possible, according to therequirement characteristics, to further implement the smaller size byusing a layered type notch filter 1001 passing the transmitting andreceiving frequency band of GSM, the transmitting frequency band ofW-CDMA and the transmitting and receiving frequency band of DCS of thelayered type duplexer and using a SAW filter 1002 utilizing a surfaceacoustic wave as the band pass filter passing the receiving frequencyband of W-CDMA.

Ninth Embodiment

Next, the configuration and operation of the 3-frequency branchingcircuit according to a ninth embodiment of the present invention will bedescribed. As the configuration and operation of the 3-frequencybranching circuit according to this embodiment are almost the same asthose in the above-mentioned sixth embodiment, the following will bedescribed as the major differences therefrom by referring to FIG. 35.(1) The branching filter of branching the low frequency band in thetransmitting and receiving frequency band of GSM from the high frequencyband in the transmitting frequency band of W-CDMA and the transmittingand receiving frequency band of DCS, (2) the switching circuit ofswitching between the transmitting and receiving of the low frequencyband in the transmitting and receiving frequency band of GSM, (3) theswitching circuit of switching between the transmitting and receiving ofthe high frequency band in the transmitting frequency band of W-CDMA andthe transmitting and receiving frequency band of DCS. Moreover, FIG. 35is an equivalent circuit diagram of the 3-frequency branching circuitaccording to this embodiment.

In FIG. 35, reference numeral 1101 denotes a first transmitting andreceiving switching circuit, 1102 denotes a second transmitting andreceiving switching circuit, and 1103 denotes the branching circuit.

A GSM transmitting circuit side terminal 1104 in the first transmittingand receiving switching circuit 1101 has the anode of a first diodeP1101 connected thereto via a first capacitor C1101, and the cathode ofthe diode P1101 is connected to the contact A. Furthermore, one end of afirst strip line L1101 is connected between the anode of the first diodeP1101 and the first capacitor C1101, and the other end of the firststrip line L1101 is connected to a control terminal 1105.

The other end of the first strip line L1101 is further connected to theground via a second capacitor C1102, and the control terminal 1105 playsa role of switching the transmitting and receiving signal of one of theGSM transmitting and receiving change-over switches. In addition, thefirst diode P1101 has a second strip line L1102 and the series circuitof a third capacitor C1103 connected thereto in parallel.

A GSM receiving circuit side terminal 1106 in the first transmitting andreceiving switching circuit 1101 has the anode of a second diode P1102connected thereto via a fourth capacitor C1104. The cathode of thesecond diode P1102 is connected to the ground via a resistor R1101 andthe parallel circuit of a fifth capacitor C1105. The anode of the seconddiode P1102 further has one end of a third strip line L1103 connectedthereto, and the other end of the third strip line L1103 is connected tothe contact A.

The first transmitting and receiving switching circuit 1101 is connectedto one end of a fourth strip line L1104 at the contact A, and the otherend of the fourth strip line L1104 is connected to a common terminal1107 of the GSM transmitting and receiving signal, the W-CDMAtransmitting signal and DCS transmitting and receiving signal via asixth capacitor C1106 through the contact C. In addition, the one end ofthe fourth strip line L1104 is connected to the ground side via a fifthstrip line L1105 and the series circuit of a seventh capacitor C1107.

A W-CDMA and DCS transmitting circuit side terminal 1108 in the secondtransmitting and receiving switching circuit 1102 has the anode of athird diode P1103 connected thereto via an eighth capacitor C1108, andthe cathode of the third diode P1103 is connected to the contact B.Furthermore, one end of a sixth strip line L1106 is connected betweenthe anode of the third diode P1103 and the eighth capacitor C1108, andthe other end of the sixth strip line L1106 is connected to a controlterminal 1109.

The other end of the sixth strip line L1106 is connected to the groundvia a ninth capacitor C1109, and the control terminal 1109 plays a roleof switching the transmitting and receiving signal of one of the W-CDMAand DCS transmitting and receiving change-over switches. In addition,the third diode P1103 further has a seventh strip line L1107 and theseries circuit of a tenth capacitor C1110 connected in parallel.

A DCS receiving circuit side terminal 1110 in the second transmittingand receiving switching circuit 1102 has the anode of a fourth diodeP1104 connected thereto via an eleventh capacitor C1111, and the cathodeof the fourth diode P1104 is connected to the ground via a resistorR1102 and the parallel circuit of a twelfth capacitor C1112. Inaddition, the anode of the fourth diode P1104 further has one end of aneighth strip line L1108 connected thereto, and the other end of theeighth strip line L1108 is connected to the contact B.

The second transmitting and receiving switching circuit 1102 isconnected to a thirteenth capacitor C1113 at the contact B, and isconnected to the common terminal 1107 of the GSM transmitting andreceiving signal, the W-CDMA transmitting signal and DCS transmittingand receiving signal via the sixth capacitor C1106 through the contactC. In addition, the one end of the thirteenth capacitor C1113 isconnected to the ground via a ninth strip line L1109 and the seriescircuit of a fourteenth capacitor C1114.

Moreover, the same results can be obtained by adding the inductanceelements instead of the resistors R1101 and R1102 and putting theresistors R1101 and R1102 between the first strip line L1101 and thecontrol terminal 1105 and between the sixth strip line L1106 and thecontrol terminal 1109 respectively.

Next, the following operation will be described while referring to FIG.36. (1) The branching filter of branching the low frequency band in thetransmitting and receiving frequency band of GSM from the high frequencyband in the transmitting frequency band of W-CDMA and the transmittingand receiving frequency band of DCS, (2) the switching circuit ofswitching between the transmitting and receiving of the low frequencyband in the transmitting and receiving frequency band of GSM, (3) theswitching circuit of switching between the transmitting and receiving ofthe high frequency band in the transmitting frequency band of W-CDMA andthe transmitting and receiving frequency band of DCS. Moreover, FIG. 36is a characteristic view of the duplexer of the 3-frequency branchingcircuit according to this embodiment.

The fourth strip line L1104, the fifth strip line L1105 and the seventhcapacitor C1107 in FIG. 35 form the low-pass filter of passing the lowfrequency as shown by the waveform 1 in FIG. 36, and the fifth stripline L1105 and the seventh capacitor C1107 are serially connected to theground side so as to form the attenuation pole point A (refer to FIG.36).

In addition, the thirteenth capacitor C1113, the ninth strip line L1109and the fourteenth capacitor C1114 in FIG. 35 form the high-pass filterof passing the high frequency as shown by the waveform 2 in FIG. 26, andthe ninth strip line L1109 and the fourteenth capacitor C1114 areserially connected to the ground side so as to form the attenuation polepoint B (refer to FIG. 36).

A connection is made via such low-pass filter and high-pass filter tothe common terminal of the GSM transmitting and receiving signal, theW-CDMA transmitting signal and DCS transmitting and receiving signal sothat, when transmitting or receiving the low frequenciesignal such asthe transmitting and receiving signal of GSM, the isolation is wellprovided to the low frequenciesignal by the attenuation pole B on thehigh-pass filter side from the contact C (refer to FIG. 35) and thesignal will not be leaked to the high-pass filter side.

Moreover, when transmitting or receiving the high frequenciesignal suchas the transmitting signal of W-CDMA and the transmitting and receivingsignal of DCS, the isolation is well provided to the highfrequenciesignal by the attenuation pole A on the low-pass filter sidefrom the contact C (refer to FIG. 35) and the signal will not be leakedto the low-pass filter side. To be more specific, the branching circuit1107 provides the function of branching the low frequenciesignal such asthe transmitting and receiving signal of GSM and the highfrequenciesignal such as the transmitting signal of W-CDMA ortransmitting and receiving signal of DCS.

In case of transmitting the low frequenciesuch as the transmittingsignal GSM, the first diode P1101 and the second diode P1102 will be inthe on state by applying the positive voltage to the control terminal1105.

At this time, the capacitors C1101, C1104 and C1106 cut the DCcomponent, and so the current does not run to each terminal. The currentvalue can be controlled by rendering the resistor R1101 variable, andthe signal transmitted from the transmitting terminal 1104 is nottransmitted to the receiving side because the impedance of the secondstrip line L1102 becomes infinite due to the second diode P1102connected to the ground side. Moreover, as the inductance component ofthe second diode P1102 resonates with the capacitor C1103, it ispossible to render the impedance infinite when seeing the receiving sidefrom the contact A at the transmitting frequency of the transmittingsignal, and the transmitting signal is transmitted to the commonterminal 1107 of the transmitting and receiving signal of GSM, thetransmitting signal of W-CDMA and transmitting and receiving signal ofDCS through the low-pass filter.

Next, on receiving, the first diode P1101 and second diode P1102 are inthe off state because no voltage is applied to the control terminal 1105so that the signal is transmitted to the receiving side from the commonterminal of the transmitting and receiving signal of GSM, thetransmitting signal of W-CDMA and transmitting and receiving signal ofDCS.

At this time, as there is the capacitance component of the first diodeP1101, the receiving signal is not always transmitted from the antennato the receiving terminal 1106, and so the capacitance component of thefirst diode P1101 is resonated with the third strip line L1103. It isthereby possible to take the isolation of the transmitting terminal 1104satisfactorily from the contact A at the receiving frequency of thereceiving signal so that the receiving signal can be transmitted via thelow-pass filter to the receiving terminal 1107 of GSM from the commonterminal 1107 of the transmitting and receiving signal of GSM, thetransmitting signal of W-CDMA and transmitting and receiving signal ofDCS.

Next, the cases of transmitting the high frequencies such as thetransmitting signal of W-CDMA or the transmitting and receiving signalof DCS will be described.

The third diode P1103 and the fourth diode P1104 will be in the on stateby applying the positive voltage to the control terminal 1109. At thistime, the capacitors C1108, C1111 and C1106 cut the DC component, and sothe current does not run to each terminal.

The current value can be controlled by rendering the resistor R1102variable, and the signal transmitted from the transmitting terminal 1108of W-CDMA and DCS is not transmitted to the receiving side becauseimpedance of the eighth strip line L1108 becomes infinite due to thefourth diode P1104 connected to the ground side.

At this time, as the inductance component of the fourth diode P1104resonates with the capacitor C1112, it is possible to render theimpedance infinite when seeing the receiving side from the contact B atthe transmitting frequency of the transmitting signal, and thetransmitting signals of W-CDMA and DCS are transmitted to the commonterminal 1107 of the transmitting and receiving signal of GSM, thetransmitting signal of W-CDMA and transmitting and receiving signal ofDCS through the high-pass filter.

In addition, on receiving DCS, no voltage is applied to the controlterminal 1109 so that the third diode P1103 and the fourth diode P1104are in the off state, and the receiving signal of DCS is transmitted tothe receiving side from the common terminal of the transmitting andreceiving signal of GSM, the transmitting signal of W-CDMA andtransmitting and receiving signal of DCS.

At this time, as there is the capacitance component of the third diodeP1103, the receiving signal of DCS is not always transmitted to thereceiving terminal 1110 from the common terminal of the transmitting andreceiving signal of GSM, the transmitting signal of W-CDMA andtransmitting and receiving signal of DCS, and so the capacitancecomponent of the third diode P1103 is resonated with the seventh stripline L1107. It is thereby possible to take the isolation of thetransmitting terminal 1108 satisfactorily from the contact B against thereceiving frequency of the receiving signal of DCS so that the receivingsignal of DCS can be efficiently transmitted via the high-pass filter tothe receiving terminal 1110 of DCS from the common terminal 1107 of thetransmitting and receiving signal of GSM, the transmitting signal ofW-CDMA and transmitting and receiving signal of DCS.

As described above, this embodiment provides the low-pass filter ofpassing the low frequency through the common terminal of thetransmitting and receiving signal of GSM, the transmitting signal ofW-CDMA and transmitting and receiving signal of DCS and the high-passfilter of passing the high frequency through it, and provides thecircuit of dividing the transmitting and receiving signals of GSM on thelow-pass filter side, and also provides the circuit of dividing thetransmitting and receiving as to the transmitting signals of W-CDMA andDCS and the receiving signal of DCS on the high-pass filter side so asto allow the transmitting and receiving of the three frequencies.

In addition, it provides the low-pass filter of passing the lowfrequency through the common terminal of the transmitting and receivingsignal of GSM, the transmitting signal of W-CDMA and transmitting andreceiving signal of DCS and the high-pass filter of passing the highfrequency through it. It is possible to eliminate undesired signals ofthe waves by two to three times more than the transmitting frequencyband of W-CDMA and DCS by using the band pass filter in the high-passfilter portion of the branching circuit.

Tenth Embodiment

Next, the configuration and operation of the 3-frequency branchingcircuit according to a tenth embodiment of the present invention will bedescribed. As the configuration and operation of the 3-frequencybranching circuit according to this embodiment are almost the same asthose in the above-mentioned sixth embodiment, the following will bedescribed as the major differences therefrom by referring to FIGS. 37 to39. (1) The branching filter of branching the high frequency band in thetransmitting frequency band of W-CDMA and the transmitting and receivingfrequency band of DCS from the low frequency band in the transmittingand receiving frequency band of GSM, (2) the switching circuit ofswitching between the transmitting and receiving of the low frequencyband in the transmitting and receiving frequency band of GSM, (3) theswitching circuit of switching between the transmitting and receiving ofthe high frequency band in the transmitting frequency band of W-CDMA andthe transmitting and receiving frequency band of DCS. Moreover, FIG. 37is a perspective view of the multilayered product of the branchingfilter of branching the low frequency band of the transmitting andreceiving frequency band of GSM and the high frequency band of thetransmitting frequency band of W-CDMA and transmitting and receivingfrequency band of DCS according to this embodiment. In addition, FIGS.38 and 39 are exploded perspective views of the lower half and upperhalf of the device including the switching circuit of switching the lowfrequency band of the transmitting and receiving frequency band of GSMand the switching circuit of switching the transmitting and receiving ofthe high frequency band of the transmitting frequency band of W-CDMA andtransmitting and receiving frequency band of DCS respectively.

In FIG. 37, a multilayered product 1301 is formed by a large number ofdielectric layers, wherein there are the branching filter of branchingthe low frequency band in the transmitting and receiving frequency bandof GSM and the high frequency bands in the transmitting frequency bandof W-CDMA and the transmitting and receiving frequency band of DCS, theswitching circuit of switching between the transmitting and receiving ofthe low frequency band in the transmitting and receiving frequency bandof GSM, and the switching circuit of switching between the transmittingand receiving of the high frequency bands in the transmitting frequencyband of W-CDMA and the transmitting and receiving frequency band of DCS.

External electrodes 1302 a, 1302 b, 1302 c, 1302 d, 1302 e, 1302 f, 1302g, 1302 h, 1302 i, 1302 j, 1302 k, 1302 l, 1302 m, 1302 n, 1302 o and1302 p are provided on and in the proximity of the sides of themultilayered product 1301.

In addition, the diodes P1101, P1102, P1103 and P1104 and the resistorR1101, and R1102 are mounted on the top face of the multilayered product1301 by soldering and so on. Moreover, the diodes may be barechip-packaged or flip chip-packaged, and the resistor may be a printedresistor.

In FIG. 38, the layer A has a first ground electrode 1401 formedtherein. In addition, the layer B has second, fifth, ninth and twelfthcapacitor coupling electrodes 1402, 1403, 1404 and 1405 formed therein,and furthermore, the layer C has a second ground electrode 1406 formedtherein.

The layers D and E have third and eighth strip line electrodes 1407 a,1407 b, 1408 a and 1408 b formed therein by dividing them in two layers.The layer F has a strip line electrode 1409 of the first strip lineformed therein. The layer G has a third ground electrode 1410 and astrip line electrode 1411 of the sixth strip line formed therein.

In FIG. 39, the layer H has a strip line electrode 1412 of the fifthstrip line, a capacitor coupling electrode 1413 of the seventh capacitorand a capacitor coupling electrode 1414 of the fourteenth capacitorformed therein.

The layer I has capacitor coupling electrodes 1415 a, 1416 a and 1417 aon one side each of the third, tenth and thirteenth capacitors formedtherein, and the layer J has capacitor coupling electrodes 1415 b, 1416b and 1417 b on the one side each of the third, tenth and thirteenthcapacitors formed therein. The layer K has capacitor coupling electrodes1415 c and 1416 c on the other side each of the third and tenthcapacitors formed therein. The layer L has capacitor coupling electrodes1418 a, 1419 a, 1420, 1421 a and 1422 a on one side each of the first,second, eighth, eleventh and sixth capacitors formed therein, andfurther has strip line electrodes 1423, 1424, 1425 and 1426 of thesecond, fourth, seventh and ninth strip lines. The layer M has capacitorcoupling electrodes 1418 b, 1419 b, 1421 b and 1422 b on one side eachof the first, second, eleventh and sixth capacitors formed therein. Thelayer N has the first, second, third and fourth diodes P1101, P1102,P1103 and P1104 and the first and second resistor R1101, and R1102mounted thereon.

Moreover, it goes without saying that the layers A to N described aboveare layered in this order.

The external electrode 1302 n (refer to FIG. 37) has the capacitorcoupling electrode 1402 connected thereto, and the capacitor couplingelectrode 1402 is sandwiched between the ground electrodes 1401 and 1406and connected to the ground. Furthermore, the external electrode 1302 nis connected to one end of the strip line electrode 1409, and the otherend of the strip line electrode 1409 is connected to the capacitorcoupling electrodes 1418 a, 1415 a and 1415 c and to the anode side ofthe diode P1101 through a via hole. The external electrode 1302 n playsa role of the control terminal, and is connected to an external controlcircuit.

The external electrode 1302 f (refer to FIG. 37) has the capacitorcoupling electrode 1418 b forming a capacitor with the capacitorcoupling electrode 1418 a connected thereto. The capacitor couplingelectrode 1415 b sandwiched between the capacitor coupling electrodes1415 a and 1415 c is connected to the cathode side of the diode P1101via the strip line electrode 1423 through the via hole.

The external electrode 1302 p (refer to FIG. 37) has the capacitorcoupling electrode 1419 a connected thereto, and the capacitor couplingelectrode 1419 b forming the capacitor with the capacitor couplingelectrode 1419 a is connected to the anode of the diode P1102 throughthe via hole.

Moreover, the cathode side of the diode P1102 is connected to one end ofthe resistor R1101, and the other end of the resistor R1101 is connectedto the ground from the external electrode 1302 o through the via hole.In addition, the cathode side of the diode P1102 is connected to thecapacitor coupling electrode 1405 through the via hole, and is connectedto the ground via the ground electrodes 1401 and 1406.

Furthermore, the capacitor coupling electrode 1419 b is connected to thecathode side of the diode P1101 via the strip line electrodes 1407 a and1407 b through the via hole. The cathode side of the diode P1101 isconnected to one end of the strip line 1425 through the via hole, andthe other end of the strip line 1425 is connected to the capacitorcoupling electrode 1422 b through the via hole.

The capacitor coupling electrode 1422 a forming the capacitor with thecapacitor coupling electrode 1422 b is connected to the externalelectrode 1302 j (refer to FIG. 37). In addition, one end of the stripline 1425 has one end of the strip line 1412 connected thereto, and theother end of the strip line 1412 is connected to the capacitor couplingelectrode 1413 to be connected to the ground via the ground electrode1410.

The external electrode 1302 l (refer to FIG. 37) has the capacitorcoupling electrode 1404 connected thereto, and the capacitor couplingelectrode 1404 is sandwiched between the ground electrodes 1401 and 1406to be connected to the ground.

The external electrode 1302 l (refer to FIG. 37) is connected to one endof the strip line electrode 1411, and the other end of the strip lineelectrode 1411 is connected to the capacitor coupling electrodes 1416 a,1416 c and to the anode side of the diode P1103 through the via hole.

The external electrode 1302 i (refer to FIG. 37) plays a role of thecontrol terminal, and is connected to the external control circuit.

The external electrode 1302 d (refer to FIG. 37) has the capacitorcoupling electrode 1420 forming the capacitor with the capacitorcoupling electrode 1416 c connected thereto. Moreover, the capacitorcoupling electrode 1416 b sandwiched between the capacitor couplingelectrodes 1416 a and 1416 c is connected to the cathode side of thediode P1103 via the strip line electrode 1424 through the via hole.

The external electrode 1302 b (refer to FIG. 37) has the capacitorcoupling electrode 1421 b connected thereto, and the capacitor couplingelectrode 1421 a forming the capacitor with the capacitor couplingelectrode 1421 b is connected to the anode of the diode P1104 throughthe via hole.

Moreover, the cathode side of the diode P1104 is connected to one end ofthe resistor R1102, and the other end of the resistor R1102 is connectedto the ground from the external electrode 1302 o through the via hole.In addition, the cathode side of the diode P1104 is connected to thecapacitor coupling electrode 1403 through the via hole, and is connectedto the ground via the ground electrodes 1401 and 1406.

Furthermore, the capacitor coupling electrode 1421 a is connected to thecathode side of the diode P1103 via the strip line electrodes 1408 a and1408 b through the via hole. The cathode side of the diode P1103 isconnected to the capacitor coupling electrode 1417 b through the viahole, and the capacitor coupling electrode 1417 a forming the capacitorwith the capacitor coupling electrode 1417 b is connected to thecapacitor coupling electrode 1422 b through the via hole.

The capacitor coupling electrode 1417 b has one end of the strip line1426 connected thereto, and the other end of the strip line 1426 isconnected to the capacitor coupling electrode 1416 through the via holeto be connected to the ground via the ground electrode 1410.

Furthermore, the external electrodes 1302 a, 1302 c, 1302 e, 1302 g,1302 i, 1302 k, 1302 m and 1302 p (refer to FIG. 37) are connected tothe ground electrodes 1401, 1406 and 1410 respectively.

In addition, the external electrode 1302 f (refer to FIG. 37) isconnected to the transmitting circuit in a subsequent stage of GSM, andthe external electrode 1302 p (refer to FIG. 37) is connected to thereceiving circuit in the subsequent stage of GSM.

The external terminal 1302 d (refer to FIG. 37) is connected to thetransmitting circuit in a subsequent stage of W-CDMA and DCS, and theexternal electrode 1302 b (refer to FIG. 37) is connected to thereceiving circuit in the subsequent stage of DCS. Furthermore, theexternal terminal 1302 j (refer to FIG. 37) is connected to the commonterminal of the transmitting and receiving signal of GSM, thetransmitting signal of W-CDMA and the transmitting and receiving signalof DCS.

It is possible, by using a multilayered substrate using the dielectricsshown in FIGS. 37 to 39, to implement the smaller sizes of the branchingfilter of branching the low frequency band in the transmitting andreceiving frequency band of GSM and the high frequency bands in thetransmitting frequency band of W-CDMA and the transmitting and receivingfrequency band of DCS, the switching circuit of switching between thetransmitting and receiving of the low frequency band in the transmittingand receiving frequency band of GSM, and the switching circuit ofswitching between the transmitting and receiving of the high frequencybands in the transmitting frequency band of W-CDMA and the transmittingand receiving frequency band of DCS of this embodiment.

In addition, it is possible to use the strip line electrodes 1409 and1411 as stubs by rendering them n times longer than wavelengths of therespective transmitting frequencies thereof so as to improve selectivityof the signals.

Furthermore, as the ground electrode is formed on the bottom face, ithas an effect that, when mounted on the mobile communication equipmentby the soldering and so on, it can be shielded from the undesiredsignals of a mounting substrate or peripheral circuit parts of themobile communication equipment.

In addition, while the strip line has one-layer or two-layer structurein the above-mentioned embodiment, the same effect can also be obtainedby rendering it as a structure of three or more layers.

Eleventh Embodiment

Next, an eleventh embodiment of the present invention will be describedby referring to FIG. 40. FIG. 40 is a perspective view of the deviceintegrating a layered duplexer 1501 portion of the 3-frequency branchingcircuit as in the eighth embodiment of the present invention and amultilayered product 1502 portion as in the eighth embodimentconstituting the branching filter of branching the low frequency band inthe transmitting and receiving frequency band of GSM and the highfrequency bands in the transmitting frequency band of W-CDMA and thetransmitting and receiving frequency band of DCS, the switching circuitof switching between the transmitting and receiving of the low frequencyband in the transmitting and receiving frequency band of GSM, and theswitching circuit of switching between the transmitting and receiving ofthe high frequency bands in the transmitting frequency band of W-CDMAand the transmitting and receiving frequency band of DCS.

It is possible, by performing such integration, to render themsmaller-size and lower-priced, and it has the effect of doing without amatching circuit required when mounting each of them on the mobilecommunication equipment by the soldering and so on.

Furthermore, as shown in FIG. 40, it is easily possible to adjust thefrequency and a degree of coupling required by the layered duplexer byhaving the configuration concurrently providing the layered duplexerportion 1501 of the 3-frequency branching circuit and a switchingcircuit portion 1502 comprised of the branching filter of branching thelow frequency band in the transmitting and receiving frequency band ofGSM and the high frequency bands in the transmitting frequency band ofW-CDMA and the transmitting and receiving frequency band of DCS, theswitching circuit of switching between the transmitting and receiving ofthe low frequency band in the transmitting and receiving frequency bandof GSM, and the switching circuit of switching between the transmittingand receiving of the high frequency bands in the transmitting frequencyband of W-CDMA and the transmitting and receiving frequency band of DCSin the tenth embodiment.

Furthermore, it is possible to implement the smaller size and lowerheight by mounting the pin diodes by wire bonding and flip chip andusing the printed resistor.

In addition, as the ground electrode is formed on the bottom face, ithas an effect that, when mounted on the mobile communication equipmentby the soldering and so on, it can be shielded from the undesiredsignals of a mounting substrate or peripheral circuit parts of themobile communication equipment.

Twelfth Embodiment

Next, a twelfth embodiment of the present invention will be described byreferring to FIG. 41. Moreover, FIG. 41 is a perspective view of thedevice of integrating a combination portion 1601 of the notch filter ofpassing the transmitting and receiving frequency band of GSM, thetransmitting frequency band of W-CDMA and the transmitting and receivingfrequency band of DCS of the layered duplexer of the 3-frequencybranching circuit as in the eighth embodiment of the present inventionand the band pass filter of passing the receiving frequency band ofW-CDMA of the duplexer of the SAW filter utilizing the surface acousticwave and a multilayered product portion 1602 constituting the branchingfilter of branching the low frequency band in the transmitting andreceiving frequency band of GSM and the high frequency bands in thetransmitting frequency band of W-CDMA and the transmitting and receivingfrequency band of DCS, the switching circuit of switching between thetransmitting and receiving of the low frequency band in the transmittingand receiving frequency band of GSM, and the switching circuit ofswitching between the transmitting and receiving of the high frequencybands in the transmitting frequency band of W-CDMA and the transmittingand receiving frequency band of DCS.

It is possible, by performing such integration, to render themsmaller-size, and it has the effect of doing without the matchingcircuit required when mounting each of them on the mobile communicationequipment by the soldering and so on.

Furthermore, it is possible to implement the smaller size and lowerheight by mounting the pin diodes by wire bonding and flip chip andusing the printed resistor.

In addition, as the ground electrode is formed on the bottom face, ithas an effect that, when mounted on the mobile communication equipmentby the soldering and so on, it can be shielded from the undesiredsignals of a mounting substrate or peripheral circuit parts of themobile communication equipment.

Thirteenth Embodiment

Next, a thirteenth embodiment of the present invention will be describedby referring to FIG. 42. Moreover, FIG. 42 is a perspective view of themultilayered product integrating a switching portion 1701 of a 1 input-4output or 1 input-5 output GaAs (gallium arsenide) having the functionof branching the branching filter of branching the low frequency band inthe transmitting and receiving frequency band of GSM and the highfrequency bands in the transmitting frequency band of W-CDMA and thetransmitting and receiving frequency band of DCS, the switching circuitof switching between the transmitting and receiving of the low frequencyband in the transmitting and receiving frequency band of GSM, and theswitching circuit of switching between the transmitting and receiving ofthe high frequency bands in the transmitting frequency band of W-CDMAand the transmitting and receiving frequency band of DCS as in the tenthembodiment into the transmitting signal and receiving signal of GSM, thetransmitting signal of W-CDMA, and the transmitting signal and receivingsignal of DCS and the layered type duplexer 1702 of the 3-frequencybranching circuit as in the eighth embodiment of the present invention.

The integration allows it to become smaller-size and lower-priced, andit has the effect of doing without the matching circuit required whenmounting each of them on the mobile communication equipment by thesoldering and so on.

Furthermore, it is possible to implement the smaller size and lowerheight by mounting GaAs (gallium arsenide) by wire bonding and flipchip.

In addition, as the ground electrode is formed on the bottom face, ithas the effect that, when mounted on the mobile communication equipmentby the soldering and so on, it can be shielded from the undesiredsignals of the mounting substrate or the peripheral circuit parts of themobile communication equipment.

Fourteenth Embodiment

Next, a fourteenth embodiment of the present invention will be describedby referring to FIG. 43. Moreover, FIG. 43 is a perspective view of thedevice integrating a switching portion 1801 of a 1 input-4 output or 1input-5 output GaAs (gallium arsenide) having the function of branchingthe branching filter of branching the low frequency band in thetransmitting and receiving frequency band of GSM and the high frequencybands in the transmitting frequency band of W-CDMA and the transmittingand receiving frequency band of DCS, the switching circuit of switchingbetween the transmitting and receiving of the low frequency band in thetransmitting and receiving frequency band of GSM, and the switchingcircuit of switching between the transmitting and receiving of the highfrequency bands in the transmitting frequency band of W-CDMA and thetransmitting and receiving frequency band of DCS as in the tenthembodiment into the transmitting signal and receiving signal of GSM, thetransmitting signal of W-CDMA, and the transmitting signal and receivingsignal of DCS respectively, and the multilayered product portion 1802integrating the combination of the notch filter passing the transmittingand receiving frequency band of GSM, the transmitting frequency band ofW-CDMA and the transmitting and receiving frequency band of DCS and theband pass filter of passing the receiving frequency band of W-CDMA ofthe duplexer of the SAW filter utilizing the surface acoustic wave ofthe layered type duplexer of the 3-frequency branching circuit as in theeighth embodiment of the present invention.

The integration allows it to become smaller-size and lower-priced, andit has the effect of doing without the matching circuit required whenmounting each of them on the mobile communication equipment by thesoldering and so on.

Furthermore, it is possible to implement the smaller size and lowerheight by mounting GaAs (gallium arsenide) and the SAW filter by wirebonding and flip chip.

In addition, as the ground electrode is formed on the bottom face, ithas the effect that, when mounted on the mobile communication equipmentby the soldering and so on, it can be shielded from the undesiredsignals of the mounting substrate or the peripheral circuit parts of themobile communication equipment.

Fifteenth Embodiment

Hereafter, the configuration and operation of the 3-frequency branchingcircuit according to a fifteenth embodiment of the present inventionwill be described by referring to FIG. 44, while taking as an examplethe circuit of the filter of passing the transmitting frequency bandsand receiving frequency bands of the three frequencies of the GSM andDCS methods used in the mobile communication in Europe and the W-CDMAmethod expected to be introduced in future. Moreover, FIG. 44 shows acircuit diagram of the 3-frequency branching circuit according to thisembodiment.

In FIG. 44, the transmitting and receiving signal from an antennaterminal 1901 as the common terminal of the transmitting and receivingof GSM, the transmitting and receiving of W-CDMA and the transmittingand receiving of DCS is branched into the transmitting and receivingsignal of GSM, the transmitting and receiving signal of W-CDMA and thetransmitting and receiving signal of DCS by a branching circuit 1902comprised of the low-pass filter and high-pass filter having a functionof branching the low frequency band and high frequency band.

The transmitting and receiving signal of GSM branched by the branchingcircuit 1902 is branched into the transmitting signal and the receivingsignal of GSM by a first transmitting and receiving switching circuit(hereafter, also referred to as a first transmitting and receivingchange-over switch) 1904 from the first internal terminal 1903 which isthe transmitting and receiving terminal of GSM.

The duplexer 1905 has broad bands such as 1710 to 1980 MHz as thetransmitting frequency band of W-CDMA and the transmitting and receivingfrequency band of DCS and 2110 to 2170 MHz as the receiving frequencyband of W-CDMA, and has the function of branching narrow bands among thebands.

1710 to 1980 MHz as the transmitting frequency band of W-CDMA and thetransmitting and receiving frequency band of DCS are branched from asecond internal terminal 1906 which is the common terminal of thetransmitting frequency band of W-CDMA, the transmitting and receivingfrequency band of DCS and the receiving frequency band of W-CDMA to afourth internal terminal 1907 which is the common terminal of thetransmitting of W-CDMA and the transmitting and receiving of DCS and toa fifth internal terminal 1908 which is the receiving terminal ofW-CDMA.

Furthermore, the transmitting signal of W-CDMA and the transmitting andreceiving signal of DCS branched by a branching circuit 1902 arebranched into the transmitting signal of W-CDMA, the transmitting signalof DCS and the receiving signal of DCS by a second transmitting andreceiving switching circuit (hereafter, also referred to as a secondtransmitting and receiving change-over switch) 1909.

In this embodiment, (1) the coaxial type duplexer described in detail inthe seventh embodiment of the present invention or (2) the layered typeduplexer described in detail in the eighth embodiment of the presentinvention and the duplexer using the SAW filter are used for theconfiguration of branching the transmitting frequency band of W-CDMA,the transmitting and receiving frequency band of DCS and the receivingfrequency band of W-CDMA.

As described above, this embodiment allows the simultaneous receiving ofW-CDMA, GSM and DCS by using the branching circuit of branching the lowfrequency band and high frequency band around the antenna portion tobranch the GSM transmitting and receiving signal from the W-CDMA and DCStransmitting and receiving signals first, using the duplexer next tobranch the W-CDMA receiving signal, using the transmitting and receivingswitching circuit to branch the GSM transmitting and receiving signal,and further using the transmitting and receiving switching circuit tobranch the W-CDMA transmitting signal and the DCS transmitting andreceiving signal.

Furthermore, the transmitting and receiving switching circuits 1904 and1909 do not pass a current for the receiving of GSM and DCS not tomention the receiving of W-CDMA, leading to reduction in the currentconsumption, and besides, it also has the effect of rendering thecircuit scale smaller, implementing the smaller size and reducinginsertion losses by simultaneously performing the transmitting of W-CDMAand the transmitting of DCS.

Moreover, in the case of taking the circuit configuration describedabove, the transmitting and receiving signal of GSM is branched first bythe branching circuit around the antenna portion and so the transmittingand receiving signal of GSM can be transmitted and received in alow-loss state so that high tone quality is assured for instance.

Sixteenth Embodiment

Next, the configuration and operation of the 3-frequency branchingcircuit according to a sixteenth embodiment of the present inventionwill be described. Here, the following will be described by referring toFIG. 45. (1) The branching filter of branching the low frequency band inthe transmitting and receiving frequency band of GSM and the highfrequency band in the transmitting frequency band of W-CDMA and thetransmitting and receiving frequency band of DCS as in the fifteenthembodiment of the present invention, (2) the switching circuit ofswitching between the transmitting and receiving of the low frequencyband in the transmitting and receiving frequency band of GSM, (3) theswitching circuit of switching between the transmitting and receiving ofthe high frequency band in the transmitting frequency band of W-CDMA andthe transmitting and receiving frequency band of DCS. Moreover, FIG. 45is an equivalent circuit diagram of the 3-frequency branching circuitaccording to this embodiment.

In FIG. 45, reference numeral 2001 denotes the first transmitting andreceiving switching circuit, 2002 denotes the second transmitting andreceiving switching circuit, and 2003 denotes the branching circuit.

A transmitting circuit side terminal 2004 of GSM on the firsttransmitting and receiving switching circuit 2001 has the anode of afirst diode P2001 connected thereto via a first capacitor C2001, and thecathode of the diode P2001 is connected to the contact A.

Furthermore, one end of a first strip line L2001 is connected betweenthe anode of the first diode P2001 and the first capacitor C2001, andthe other end of the first strip line L2001 is connected to a controlterminal L2005.

The other end of the first strip line L2001 is further connected to theground via a second capacitor C2002, and the control terminal 2005 playsa role of switching the transmitting and receiving signal of one of thetransmitting and receiving change-over switches of GSM. In addition, thefirst diode P2001 has a second strip line L2002 and a series circuit ofa third capacitor C2003 connected in parallel thereto.

A receiving circuit side terminal 2006 of GSM in the first transmittingand receiving switching circuit 2001 is connected to the anode of asecond diode P2002 via a fourth capacitor C2004.

The cathode of the second diode P2002 is connected to the ground via aresistor R2001 and the parallel circuit of a fifth capacitor C2005. Theanode of the second diode P2002 is further connected to one end of athird strip line L2003, and the other end of the third strip line L2003is connected to the contact A.

The first transmitting and receiving switching circuit 2001 is connectedto one end of a fourth strip line L2004 at the contact A, and the otherend of the fourth strip line L2004 is connected to a common terminal2007 of the transmitting and receiving signal of GSM, the transmittingand receiving signal of W-CDMA and the transmitting and receiving signalof DCS through the contact C and via a sixth capacitor C2006. Inaddition, the one end of the fourth strip line L2004 is connected to theground side via a fifth strip line L2005 and the series circuit of aseventh capacitor C2007.

A common terminal 2008 of the transmitting and receiving signal ofW-CDMA and the transmitting and receiving signal of DCS is connected toan eighth capacitor C2008, and is connected to the common terminal 2007of the transmitting and receiving signal of GSM, the transmitting andreceiving signal of W-CDMA and the transmitting and receiving signal ofDCS through the contact C and via the sixth capacitor C2006. Inaddition, the common terminal 2008 of the transmitting and receivingsignal of W-CDMA and the transmitting and receiving signal of DCS isconnected to the ground side via a ninth strip line L2009 and the seriescircuit of a fifteenth capacitor C2015.

A transmitting circuit side terminal 2009 of W-CDMA and DCS in thesecond transmitting and receiving switching circuit 2002 is connected tothe anode of a third diode P2003 via the ninth capacitor C2009, and thecathode of the third diode P2003 is connected to the contact B.

Furthermore, one end of a sixth strip line L2006 is connected betweenthe anode of the third diode P2003 and the ninth capacitor C2009, andthe other end of the sixth strip line L2006 is connected to a controlterminal 2009. In addition, the other end of the sixth strip line L2006is further connected to the ground via a tenth capacitor C2010, and acontrol terminal 2010 plays a role of switching the transmitting andreceiving signal of one of the transmitting and receiving change-overswitches of W-CDMA and DCS.

The third diode P2003 further has a seventh strip line L2007 and aseries circuit of an eleventh capacitor C2011 connected in parallelthereto.

A receiving circuit side terminal 2011 of DCS in the second transmittingand receiving switching circuit 2002 is connected to the anode of afourth diode P2004 via a twelfth capacitor C2012, and the cathode of thefourth diode P2004 is connected to the ground via a resistor R2002 and aparallel circuit of a thirteenth capacitor C2013.

The anode of the fourth diode P2004 is further connected to one end ofan eighth strip line L2008, and the other end of the eighth strip lineL2008 is connected to the contact B.

The second transmitting and receiving switching circuit 2002 isconnected to a fourteenth capacitor C2014 at the contact B, and isconnected to a common terminal 2012 of the transmitting and receivingsignal of W-CDMA and the transmitting and receiving signal of DCS.

Moreover, the same results can also be obtained by adding the inductanceelements instead of the resistors R2001 and R2002 and putting theresistors R2001 and R2002 between the first strip line L2001 and thecontrol terminal 2005 and between the sixth strip line L2006 and thecontrol terminal 2009 respectively.

Next, the operation of the following constituted as above will bedescribed while referring to FIG. 36. (1) The branching filter ofbranching the low frequency band in the transmitting and receivingfrequency band of GSM and the high frequency band in the transmittingfrequency band of W-CDMA and the transmitting and receiving frequencyband of DCS, (2) the switching circuit of switching between thetransmitting and receiving of the low frequency band in the transmittingand receiving frequency band of GSM, (3) the switching circuit ofswitching between the transmitting and receiving of the high frequencyband in the transmitting frequency band of W-CDMA and the transmittingand receiving frequency band of DCS.

The fourth strip line L2004, the fifth strip line L2005 and the seventhcapacitor C2007 form the low-pass filter of passing the low frequency asshown by the waveform 1 in FIG. 36, and the fifth strip line L2005 andthe seventh capacitor C2007 are serially connected to the ground side soas to form the attenuation pole point A (refer to FIG. 36).

In addition, the thirteenth capacitor C2013, the ninth strip line L2009and the fourteenth capacitor C2014 form the high-pass filter of passingthe high frequency as shown by the waveform 2 in FIG. 36, and the ninthstrip line L2009 and the fourteenth capacitor C2014 are seriallyconnected to the ground side so as to form the attenuation pole point B(refer to FIG. 36).

A connection is made via such low-pass filter and high-pass filter tothe common terminal of the transmitting and receiving signal of GSM, thetransmitting and receiving signal of W-CDMA and the transmitting andreceiving signal of DCS so that, when transmitting or receiving the lowfrequenciesignal such as the transmitting and receiving signal of GSM,the isolation is well provided to the low frequenciesignal by theattenuation pole B on the high-pass filter side from a contact C and thesignal will not be leaked to the high-pass filter side.

Moreover, when transmitting or receiving the high frequenciesignal suchas the transmitting and receiving frequenciesignals of W-CDMA and thoseof DCS, the isolation is well provided to the high frequenciesignal bythe attenuation pole A on the low-pass filter side from the contact Cand the signal will not be leaked to the low-pass filter side.

To be more specific, the branching circuit 2003 provides the function ofbranching the low frequenciesignal such as the transmitting andreceiving signal of GSM and the high frequenciesignal such as thetransmitting and receiving frequenciesignal of W-CDMA and that of DCS.

In the case of transmitting the low frequenciesignal such as thetransmitting signal of GSM, the first diode P2001 and the second diodeP2002 will be in the on state by applying the positive voltage to thecontrol terminal 2005.

At this time, the capacitors C2001, C2004 and C2006 cut the DCcomponent, and so the current does not run to each terminal. Moreover,the current value can be controlled by rendering the resistor R2001variable, and as to the signal transmitted from the transmittingterminal 2004, the impedance of the second strip line L2002 becomesinfinite due to the second diode P2002 connected to the ground side.Thus, the signal transmitted from the transmitting terminal 2004 is nottransmitted to the receiving side.

As the inductance component of the second diode P2002 resonates with thecapacitor C2003, it is possible to render the impedance infinite whenseeing the receiving side from the contact A at the transmittingfrequency of the transmitting signal, and the transmitting signal istransmitted to a common terminal 2007 of the transmitting and receivingsignal of GSM, the transmitting and receiving signal of W-CDMA and thetransmitting and receiving signal of DCS through the low-pass filter.

Next, on receiving, the first diode P2001 and second diode P2002 are inthe off state because no voltage is applied to the control terminal 2005so that the signal is transmitted to the receiving side from the commonterminal of the transmitting and receiving signal of GSM, thetransmitting and receiving signal of W-CDMA and the transmitting andreceiving signal of DCS.

At this time, as there is the capacitance component of the first diodeP2001, the receiving signal is not always transmitted from the antennato the receiving terminal 2006, and so the capacitance component of thefirst diode P2001 is resonated with the third strip line L2003. It isthereby possible to take the isolation of the transmitting terminal 2004satisfactorily from the contact A at the receiving frequency of thereceiving signal so that the receiving signal can be transmitted to thereceiving terminal 2006 of GSM from the common terminal 2007 of thetransmitting and receiving signal of GSM, the transmitting signal ofW-CDMA and the transmitting and receiving signal of DCS via the low-passfilter.

Next, the cases of transmitting the high frequencies such as thetransmitting and receiving signal of W-CDMA or that of DCS will bedescribed.

The third diode P2003 and the fourth diode P2004 will be in the on stateby applying the positive voltage to the control terminal 2010. At thistime, the capacitors C2009, C2012 and C2014 cut the DC component, and sothe current does not run to each terminal.

The current value can be controlled by rendering the resistor R2002variable, and the signal transmitted from the transmitting terminal 2009of W-CDMA and DCS is not transmitted to the receiving side because theimpedance of the eighth strip line L2008 becomes infinite due to thefourth diode P2004 connected to the ground side.

At this time, as the inductance component of the fourth diode P2004resonates with the capacitor C2012, it is possible to render theimpedance infinite when seeing the receiving side from the contact B atthe transmitting frequency of the transmitting signal, and thetransmitting signal is transmitted to a common terminal 2012 of thetransmitting signal of W-CDMA and the transmitting and receiving signalof DCS.

Next, on receiving of DCS, the third diode P2003 and fourth diode P2004are in the off state because no voltage is applied to the controlterminal 2010 so that the receiving signal of DCS is transmitted to thereceiving side from the common terminal of the transmitting signal ofW-CDMA and the transmitting and receiving signal of DCS.

At this time, as there is the capacitance component of the third diodeP2003, the receiving signal of DCS is not always transmitted to thereceiving terminal 2011 from the common terminal of the transmittingsignal of W-CDMA and the transmitting and receiving signal of DCS, andso the capacitance component of the third diode P2003 is resonated withthe seventh strip line L2007. It is thereby possible to take theisolation of the transmitting terminal 2009 satisfactorily from thecontact B to the receiving frequency of the receiving signal of DCS sothat the receiving signal of DCS can be efficiently transmitted to thecommon terminal 2012 of the transmitting signal of W-CDMA and thetransmitting and receiving signal of DCS.

As described above, this embodiment provides the low-pass filter ofpassing the low frequency through the common terminal of thetransmitting and receiving signal of GSM, the transmitting signal ofW-CDMA and transmitting and receiving signal of DCS and the high-passfilter of passing the high frequency through it, and provides thecircuit of dividing the transmitting and receiving signals of GSM on thelow-pass filter side, and also provides the circuit of dividing thetransmitting and receiving as to the transmitting signals of W-CDMA andDCS and the receiving signal of DCS on the high-pass filter side so asto allow the transmitting and receiving of the three frequencies.

In addition, it is possible to eliminate the undesired signals of thewaves by two to three times more than the transmitting frequency band ofW-CDMA and DCS by using the band pass filter in the high-pass filterportion of the branching circuit having the low-pass filter of passingthe low frequency through the common terminal of the transmitting andreceiving signal of GSM, the transmitting signal of W-CDMA andtransmitting and receiving signal of DCS and the high-pass filter ofpassing the high frequency through it.

Seventeenth Embodiment

Next, the configuration and operation of the 3-frequency branchingcircuit according to a seventeenth embodiment of the present inventionwill be described. As the configuration and operation of the 3-frequencybranching circuit according to this embodiment are almost the same asthose in the above-mentioned fifteenth embodiment, the configuration andoperation of the following will be described as the major differencestherefrom by referring to FIGS. 46 to 48. (1) The branching filter ofbranching the low frequency band in the transmitting and receivingfrequency band of GSM and the high frequency band in the transmittingand receiving frequency band of W-CDMA and the transmitting andreceiving frequency band of DCS, (2) the switching circuit of switchingbetween the transmitting and receiving of the low frequency band in thetransmitting and receiving frequency band of GSM, (3) the switchingcircuit of switching between the transmitting and receiving of the highfrequency band in the transmitting frequency band of W-CDMA and thetransmitting and receiving frequency band of DCS. Moreover, FIG. 22 is aperspective view of the multilayered product of the branching filter ofbranching the low frequency band of the transmitting and receivingfrequency band of GSM and the high frequency band of the transmittingand receiving frequency band of W-CDMA and the transmitting andreceiving frequency band of DCS according to this embodiment. Inaddition, FIGS. 47 and 48 are exploded perspective views of the upperhalf and lower half of the device including the switching circuit ofswitching between the transmitting and receiving of the low frequencyband of the transmitting and receiving frequency band of GSM and theswitching circuit of switching between the transmitting and receiving ofthe high frequency band of the transmitting frequency band of W-CDMA andtransmitting and receiving frequency band of DCS respectively.

In FIG. 46, a multilayered product 2101 of the branching filter ofbranching the low frequency band in the transmitting and receivingfrequency band of GSM and the high frequency band in the transmittingfrequency band of W-CDMA and the transmitting and receiving frequencyband of DCS, the switching circuit of switching between the transmittingand receiving of the low frequency band in the transmitting andreceiving frequency band of GSM, and the switching circuit of switchingbetween the transmitting and receiving of the high frequency band in thetransmitting frequency band of W-CDMA and the transmitting and receivingfrequency band of DCS is formed by a large number of dielectric layers.

External electrodes 2102 a, 2102 b, 2102 c, 2102 d, 2102 e, 2102 f, 2102g, 2102 h, 2102 i, 2102 j, 2102 k, 2102 l, 2102 m, 2102 n, 2102 o and2102 p are provided on and in the proximity of the sides of themultilayered product 2101.

In addition, the diodes P2001, P2002, P2003 and P2004 and the resistorR2001, and R2002 are mounted on the top face of the multilayered product2101 by soldering and so on. Moreover, the diodes may be barechip-packaged or flip chip-packaged, and the resistor may be the printedresistor.

In FIG. 47, the layer A has a first ground electrode 2201 formedtherein. In addition, the layer B has second, fifth, tenth andthirteenth capacitor coupling electrodes 2202, 2203, 2204 and 2205formed therein, and furthermore, the layer C has a second groundelectrode 2206 formed therein.

The layers D and E have strip line electrodes 2207 a, 2207 b, 2208 a and2208 b of the third and eighth strip lines formed therein by dividingthem in two layers. In addition, the layer F has a strip line electrode2209 of the first strip line and one capacitor coupling electrode 2210 aof a fourteenth capacitor formed therein.

The layer G has a third ground electrode 2211, a strip line electrode2212 of the sixth strip line and the other capacitor coupling electrode2210 b of the fourteenth capacitor formed therein.

In FIG. 48, the layer H has a strip line electrode 2213 of the fifthstrip line, a capacitor coupling electrode 2214 of the seventh capacitorand a capacitor coupling electrode 2215 of the fifteenth capacitorformed therein.

The layer I has capacitor coupling electrodes 2216 a, 2217 a and 2218 aon one side each of the third, eleventh and eighth capacitors formedtherein, and the layer J has capacitor coupling electrodes 2216 b, 2217b and 2218 b on the one side each of the third, eleventh and eighthcapacitors formed therein. The layer K has capacitor coupling electrodes2216 c, 2217 c and 2218 c on the other side each of the third, eleventhand eighth capacitors formed therein. The layer L has capacitor couplingelectrodes 2219 a, 2220 a, 2221 a, 2222 a, and 2223 a on one side eachof the first, fourth, ninth, twelfth and sixth capacitors formedtherein, and further has strip line electrodes 2224, 2225, 2226, and2227 of the second, fourth, seventh and ninth strip lines formedtherein. The layer M has capacitor coupling electrodes 2219 b, 2220 b,2222 b and 2223 b on one side each of the first, fourth, twelfth andsixth capacitors formed therein. The layer N has the first, second,third and fourth diodes P2001, P2002, P2003 and P2004 and the first andsecond resistor R2001, and R2002 mounted thereon.

Moreover, it goes without saying that the layers A to N described aboveare layered in this order.

The external electrode 2102 n (refer to FIG. 46) has the capacitorcoupling electrode 2202 connected thereto, and the capacitor couplingelectrode 2202 is sandwiched between the ground electrode 2201 and 2206and connected to the ground.

Furthermore, the external electrode 2102 n (refer to FIG. 46) isconnected to one end of the strip line electrode 2209, and the other endof the strip line electrode 2209 is connected to the capacitor couplingelectrodes 2219 a, 2216 a and 2216 c and to the anode side of the diodeP2001 through the via hole. In addition, the external electrode 2102 nplays a role of the control terminal, and is connected to the externalcontrol circuit.

The external electrode 2102 f (refer to FIG. 46) has the capacitorcoupling electrode 2219 b forming a capacitor with the capacitorcoupling electrode 2219 a connected thereto. The capacitor couplingelectrode 2216 b sandwiched between the capacitor coupling electrodes2216 a and 2216 c is connected to the cathode side of the diode P2001(refer to FIG. 46) via the strip line electrode 2224 through the viahole.

The external electrode 2102 p (refer to FIG. 46) has the capacitorcoupling electrode 2220 a connected thereto, and the capacitor couplingelectrode 2220 b forming the capacitor with the capacitor couplingelectrode 2220 a is connected to the anode of the diode P2002 throughthe via hole. Moreover, the cathode side of the diode P2002 (refer toFIG. 46) is connected to one end of the resistor R2001, and the otherend of the resistor R2001 is connected to the ground from the externalelectrode 21020 through the via hole. In addition, the cathode side ofthe diode P2002 is connected to the capacitor coupling electrode 2205through the via hole, and is connected to the ground via the groundelectrodes 2201 and 2206.

The capacitor coupling electrode 2220 b is connected to the strip lineelectrode 2207 a through the via hole, and is connected to the cathodeside of the diode P2001 via 2207 b.

The cathode side of the diode P2001 (refer to FIG. 46) is connected toone end of the strip line 2225 through the via hole, and the other endof the strip line 2225 is connected to the capacitor coupling electrode2223 b through the via hole.

The capacitor coupling electrode 2223 a forming the capacitor with thecapacitor coupling electrode 2223 b is connected to the externalelectrode 2102 j. In addition, one end of the strip line 2225 has oneend of the strip line 2213 connected thereto, and the other end of thestrip line 2213 is connected to the capacitor coupling electrode 2214 tobe connected to the ground via the ground electrode 2211. In addition,the other end of the strip line 2225 is connected to the capacitorcoupling electrode 2223 b.

Moreover, the capacitor coupling electrode 2223 a forming the capacitorwith the capacitor coupling electrode 2223 b is connected to theexternal electrode 2102 j (refer to FIG. 46). In addition, the other endof the strip line 2225 is connected to the capacitor coupling electrode2218 b, and the capacitor coupling electrode 2218 a forming thecapacitor with the capacitor coupling electrode 2218 b is connected tothe external electrode 2102 c (refer to FIG. 46).

The external electrode 2102 l (refer to FIG. 46) has the capacitorcoupling electrode 2204 connected thereto, and the capacitor couplingelectrode 2204 is sandwiched between the ground electrodes 2201 and 2206to be connected to the ground. Furthermore, the external electrode 2102l is connected to one end of the strip line electrode 2212, and theother end of the strip line electrode 2212 is connected to the capacitorcoupling electrodes 2217 a, 2217 c and to the anode side of the diodeP2003 through the via hole. In addition, the external electrode 2102 lplays a role of the control terminal, and is connected to the externalcontrol circuit.

The external electrode 2102 d (refer to FIG. 46) has the capacitorcoupling electrode 2221 forming the capacitor with the capacitorcoupling electrode 2217 c connected thereto. The capacitor couplingelectrode 2217 b sandwiched between the capacitor coupling electrodes2217 a and 2217 c is connected to the cathode side of the diode P2003(refer to FIG. 46) via the strip line electrode 2226 through the viahole.

The external electrode 2102 b (refer to FIG. 46) has the capacitorcoupling electrode 2222 b connected thereto, and the capacitor couplingelectrode 2222 a forming the capacitor with the capacitor couplingelectrode 2222 b is connected to the anode of the diode P2004 throughthe via hole. Moreover, the cathode side of the diode P2004 is connectedto one end of the resistor R2002, and the other end of the resistorR2002 is connected to the ground from the external electrode 2102 othrough the via hole. In addition, the cathode side of the diode P2004is connected to the capacitor coupling electrode 2203 through the viahole, and is connected to the ground via the ground electrodes 2201 and2206.

Furthermore, the capacitor coupling electrode 2222 a is connected to thecathode side of the diode P2003 via the strip line electrodes 2208 a and2208 b through the via hole. Moreover, the cathode side of the diodeP2003 is connected to the capacitor coupling electrode 2210 b throughthe via hole, and the capacitor coupling electrode 2210 a forming thecapacitor with the capacitor coupling electrode 2210 b is connected tothe external electrode 2102 g through the via hole.

Furthermore, the external electrodes 2102 a, 2102 e, 2102 h, 2102 i,2102 k, 2102 m and 2102 o (refer to FIG. 46) are connected to theterminals of the ground electrodes 2201 and 2206 (each has seven) and2211 (it has three) in compliance with a predetermined rule.

The external electrode 2102 f (refer to FIG. 46) is connected to thetransmitting circuit in the subsequent stage of GSM, and the externalelectrode 2102 p (refer to FIG. 46) is connected to the receivingcircuit in the subsequent stage of GSM.

An external terminal 2102 c (refer to FIG. 46) is connected to thecommon terminal of the transmitting and receiving signal of W-CDMA andthe transmitting and receiving signal of DCS of the duplexer ofbranching the transmitting signal of W-CDMA, the transmitting andreceiving signal of DCS and the receiving signal of W-CDMA, and anexternal terminal 2102 d (refer to FIG. 46) is connected to thetransmitting circuit in the subsequent stage of W-CDMA and DCS and anexternal terminal 2102 b (refer to FIG. 46) is connected to thereceiving circuit in the subsequent stage of DCS.

An external terminal 2102 g (refer to FIG. 46) is connected to thecommon terminal of the transmitting signal of W-CDMA and thetransmitting and receiving signal of DCS of the duplexer of branchingthe transmitting signal of W-CDMA, the transmitting and receiving signalof DCS and the receiving signal of W-CDMA, and the external terminal2102 d (refer to FIG. 46) is connected to the transmitting circuit inthe subsequent stage of W-CDMA and DCS. Furthermore, an externalterminal 2102 j is connected to the antenna terminal.

It is possible, by using the multilayered substrate using thedielectrics shown in FIGS. 46 to 48, to implement the smaller sizes ofthe branching filter of branching the low frequency band in thetransmitting and receiving frequency band of GSM and the high frequencybands in the transmitting frequency band of W-CDMA and the transmittingand receiving frequency band of DCS, the switching circuit of switchingbetween the transmitting and receiving of the low frequency band in thetransmitting and receiving frequency band of GSM, and the switchingcircuit of switching between the transmitting and receiving of the highfrequency bands in the transmitting frequency band of W-CDMA and thetransmitting and receiving frequency band of DCS of the presentinvention.

Moreover, it is possible to use the strip line electrodes 2209 and 2211(refer to FIG. 47) as stubs by rendering them n times longer thanwavelengths of the respective transmitting frequencies thereof so as toimprove selectivity of the signals.

Furthermore, as the ground electrode is formed on the bottom face, ithas an effect that, when mounted on the mobile communication equipmentby the soldering and so on, it can be shielded from the undesiredsignals of a mounting substrate or peripheral circuit parts of themobile communication equipment.

In addition, while the strip line has one-layer or two-layer structurein this embodiment, the same effect can also be obtained by rendering itas the structure of three or more layers.

Eighteenth Embodiment

Hereafter, the 3-frequency branching circuit according to an eighteenthembodiment of the present invention will be described by referring toFIG. 49, while taking as a concrete example the circuit of the filter ofpassing the transmitting frequency bands and receiving frequency bandsof the three frequencies of the GSM and DCS methods used in the mobilecommunication in Europe and the W-CDMA method expected to be introducedin future. Moreover,

FIG. 49 shows a circuit diagram of the 3-frequency branching circuitaccording to the eighteenth embodiment.

In FIG. 49, reference numeral 2301 denotes the filter of which bandwidths are broad bands such as 880 to 960 MHz as the transmitting andreceiving frequency band of GSM, 1710 to 1980 MHz as the transmittingfrequency band of W-CDMA and the transmitting and receiving frequencyband of DCS, and 2110 to 2170 MHz as the receiving frequency band ofW-CDMA, and having the function of branching the narrow bands among thebands.

880 to 960 MHz which is the transmitting and receiving frequency band ofGSM is branched by the low-pass filter having the function of branchingthe low frequency band from an antenna terminal 2302 to a first internalterminal 2303. In addition, 1710 to 1980 MHz which is the transmittingfrequency band of W-CDMA and the transmitting and receiving frequencyband of DCS is branched by the band pass filter having the function ofbranching the intermediate frequency band from the antenna terminal 2302to a second internal terminal 2304. And 2110 to 2170 MHz which is thereceiving frequency band of W-CDMA is branched by the high-pass filterhaving the function of branching the high frequency band from theantenna terminal 2302 to a third internal terminal 2305.

The transmitting and receiving signal of GSM branched by the low-passfilter is branched into the transmitting signal and receiving signal ofGSM by a first transmitting and receiving switching circuit (hereafter,also referred to as the first transmitting and receiving change-overswitch) 2306. In addition, the transmitting signal of W-CDMA and thetransmitting and receiving signal of DCS branched by the band passfilter are branched into the transmitting signal of W-CDMA, thetransmitting signal of DCS and the receiving signal of DCS by a secondtransmitting and receiving switching circuit (hereafter, also referredto as the second transmitting and receiving change-over switch) 2307.

As described above, this embodiment allows the simultaneous receiving ofW-CDMA, GSM and DCS by branching around the antenna portion (1) thetransmitting and receiving of GSM, (2) the transmitting of the W-CDMAand the transmitting and receiving of DCS and (3) the receiving ofW-CDMA. Furthermore, it can do without an external matching circuitbecause the three frequencies are constituted by one circuit.

In addition, the transmitting and receiving switching circuits 2306 and2307 do not pass the current on receiving of GSM and DCS not to mentionreceiving of W-CDMA, leading to reduction in current consumption.Furthermore, it also has the effect of rendering the circuit scalesmaller, implementing the smaller size and reducing insertion losses bysimultaneously performing the transmitting of W-CDMA and thetransmitting of DCS.

Nineteenth Embodiment

Next, a nineteenth embodiment of the present invention will be describedby referring to FIGS. 50 to 52.

The configuration and operation of a coaxial type duplexer of the3-frequency branching circuit according to a nineteenth embodiment ofthe present invention will be described by using FIGS. 50 to 52.Moreover, FIG. 50 is an equivalent circuit diagram of the coaxial type,FIG. 51 is a top view thereof, and FIG. 52 is a characteristic viewthereof.

In FIG. 50, a W-CDMA receiving terminal 2401 has a first capacitor C2401connected to the ground and a first inductor L2401 connected thereto.

The other end of the first inductor L2401 is connected to a coaxial typeresonator Res2401 via a second capacitor C2402. In addition, a thirdcapacitor C2403 is connected to the ground and furthermore, a secondinductor L2402 is connected thereto.

The other end of the second inductor L2402 is connected to a coaxialtype resonator Res2402 via a fourth capacitor C2404. In addition, afifth capacitor C2405 is connected to the ground, and a third inductorL2403 is connected thereto. Moreover, the other end of the thirdinductor L2403 is connected to an antenna terminal 2402 to be connectedto the antenna.

A W-CDMA transmitting and DCS transmitting and receiving terminal 2403has a sixth capacitor C2406 connected thereto, and the other end of thesixth capacitor C2406 is connected to a coaxial type resonator Res2403in parallel, and is connected to a seventh capacitor C2407 and furtherto an eighth capacitor C2408.

The other end of the eighth capacitor C2408 is connected to a coaxialtype resonator Res2404 in parallel, and is connected to a ninthcapacitor C2409. The other end of the ninth capacitor C2409 is connectedto a coaxial type resonator Res2405 in parallel, and is connected to theother end of the seventh capacitor C2407 and further to a tenthcapacitor C2410 and to the antenna terminal 2402.

A GSM transmitting and receiving terminal 2404 is connected to aneleventh capacitor C2411 connected to the ground, and is also connectedto a fourth inductor L2404.

The other end of the fourth inductor L2404 has a twelfth capacitor C2412connected to the ground, and also has a fifth inductor L2405 connectedthereto.

The other end of the fifth inductor L2405 is connected to the antennaterminal 2402 to be connected to the antenna.

The configuration of the coaxial type comprised of the equivalentcircuit as above will be described by using FIG. 51.

In FIG. 51, a wiring substrate P2501 is made of glass epoxy and so on.Moreover, coaxial type resonators Res2401 to 2405 (refer to FIG. 50) aremade of dielectrics and so on, and are mounted on the wiring substrateP2501 by the soldering and so on together with the inductor elementssuch as the air core coil and chip capacitor.

External terminals 2501, 2502, 2503, 2504, 2505, 2506, 2507, 2508, 2509and 2510 are provided on the wiring substrate P2501. In addition, theexternal terminals 2501 is connected to the receiving terminal ofW-CDMA, the external terminals 2509 to the antenna terminal, theexternal terminals 2507 to the transmitting and receiving terminal ofGSM, and the external terminals 2508 to the transmitting terminal ofW-CDMA and the transmitting and receiving terminal of DCS respectively,and the external terminals 2502, 2503, 2504, 2505, 2506 and 2510 havethe ground terminals placed thereon.

In FIG. 52, the waveform 1 is a waveform diagram of the transmitting andreceiving signal of GSM. In the waveform 1, the transmitting andreceiving frequency band of GSM is passed by using the low-pass filter.In addition, the selectivity is improved by attenuating the transmittingand receiving frequency band of W-CDMA and the transmitting andreceiving frequency band of DCS.

The waveform 2 is a waveform diagram of the transmitting signal ofW-CDMA and the transmitting and receiving signal of DCS. In the waveform2, the transmitting frequency band of W-CDMA and the transmitting andreceiving frequency band of DCS are passed by using the band passfilter. Moreover, the selectivity is improved by attenuating thetransmitting and receiving frequency band of GSM and the receivingfrequency band of W-CDMA.

The waveform 3 is a waveform diagram of the receiving signal of W-CDMA.In the waveform 3, the receiving frequency band of W-CDMA is passed byusing the notch filter. Moreover, the selectivity is improved byattenuating the transmitting and receiving frequency band of GSM, thetransmitting frequency band of W-CDMA and the transmitting and receivingfrequency band of DCS.

As described above, it is possible, according to this embodiment, toreduce the insertion losses of the transmitting and receiving signal ofGSM, the transmitting signal of W-CDMA, the transmitting and receivingsignal of DCS and the receiving signal of W-CDMA by using the duplexerand using the coaxial type.

Twentieth Embodiment

Next, a twentieth embodiment of the present invention will be describedby referring to the drawings. Moreover, FIGS. 53 to 55 are a perspectiveview, an exploded perspective view and an equivalent circuit diagram ofthe multilayered product constituting the 3-frequency branching circuitaccording to the twentieth embodiment of the present invention.

In FIG. 53, a multilayered product 2701 of the 3-frequency branchingcircuit is formed by a large number of the dielectric layers, andexternal electrodes 2702, 2703, 2704, 2705, 2706, 2707, 2708, 2709,2710, 2711, 2712 and 2713 are provided on and in the proximity of thesides of the multilayered product 2701.

The configuration and circuit will be described in detail by referringto FIGS. 54 and 55.

The layer A in FIG. 54 has a first ground electrode 2801 formed therein.In addition, the layer B has first, second, third, fourth and fifthresonator electrodes 2802, 2803, 2804, 2805 and 2806 formed therein, andfurthermore, the layer C has first and second capacitor couplingelectrodes 2807 and 2808 formed therein.

The layer D has third, fourth, fifth, sixth and seventh capacitorcoupling electrodes 2809, 2810, 2811, 2812 and 2816 and first, second,third and fourth strip line electrodes 2813, 2814, 2815 and 2817 formedtherein.

The layers E, F and G have eighth, ninth, tenth, eleventh and twelfthcapacitor coupling electrodes 2818, 2819, 2820, 2821 and 2822 formedtherein. Furthermore, the layer H has a second ground electrode 2823formed therein.

The external electrode 2711 (refer to FIG. 53) is the receiving terminalof W-CDMA, and the external electrode 2811 (refer to FIG. 54) has thestrip line electrode 2814 connected thereto. Furthermore, the externalelectrode 2811 is connected to the ground by the ground electrode 2823(refer to FIG. 54) via the capacitor coupling electrode 2822.

One end of the strip line electrode 2814 is connected to one end of thecapacitor coupling electrode 2812, and the capacitor coupling electrode2812 is connected to the resonator electrode 2802 via the layers C andD.

The other end of the capacitor coupling electrode 2812 is connected toone end of the capacitor coupling electrode 2811, and the capacitorcoupling electrode 2811 is connected to the resonator electrode 2803 viathe layers C and D.

The other end of the capacitor coupling electrode 2811 is connected toone end of the strip line electrode 2813, and one end of the strip lineelectrode 2813 is connected to one end of the capacitor couplingelectrode 2820 (refer to FIG. 54) via the layers E and F. The other endof the capacitor coupling electrode 2820 is connected to the ground bythe external electrode 2713 (refer to FIG. 53), and furthermore, theother end of the strip line electrode 2813 is connected to the externalelectrode 2702 (refer to FIG. 53) which is the antenna terminal so as toform the notch filter structure.

The external electrode 2705 (refer to FIG. 53) is the DCS transmittingand receiving and W-CDMA transmitting terminal, and is connected to oneend of the capacitor coupling electrode 2818. The capacitor couplingelectrode 2818 is connected to the resonator electrode 2804 via thelayers C, D and E.

The resonator electrode 2804 is connected to the capacitor couplingelectrode 2807 via the layer C, and the capacitor coupling electrode2807 is connected to the resonator electrode 2805 via the layer C. Inaddition, the resonator electrode 2805 is connected to the capacitorcoupling electrode 2808 via the layer C, and the capacitor couplingelectrode 2808 is connected to the resonator electrode 2806 via thelayer C. Furthermore, the capacitor coupling electrode 2807 is connectedto the capacitor coupling electrode 2808 via the layer D.

The resonator electrode 2806 is connected to the capacitor couplingelectrode 2810 via the layers C and D, and the capacitor couplingelectrode 2810 is connected to the external electrode 2702 (refer toFIG. 53) which is the antenna terminal so as to form the band-passfilter structure.

The external electrode 2708 (refer to FIG. 53) is the GSM transmittingand receiving terminal, and the external electrode 2708 is connected toone end of the capacitor coupling electrode 2821, and the capacitorcoupling electrode 2821 has the ground electrode 2823 (refer to FIG. 54)connected thereto via the layers G and H. Furthermore, the externalelectrode 2708 has the strip line electrode 2817 connected thereto, andthe other end of the strip line electrode 2817 is connected to thecapacitor coupling electrode 2816, and is connected to the capacitorcoupling electrode 2819 (refer to FIG. 54) via the layer E. In addition,the capacitor coupling electrode 2819 is connected to the ground via theexternal electrode 2706 (refer to FIG. 53).

The capacitor coupling electrode 2816 is connected to the strip lineelectrode 2815, and the other end of the strip line electrode 2815 isconnected to the external electrode 2702 (refer to FIG. 53) which is theantenna terminal so as to form the low-pass filter structure. Moreover,the external electrodes 2703, 2704, 2706, 2707, 2709, 2710, 2712 and2713 (refer to FIG. 53) form the ground electrode.

As described above, according to this embodiment, it is possible toimplement the smaller size by using the layered type duplexer.

Moreover, this embodiment was described in detail by taking the layeredtype duplexer as an example, but it is also possible to implement thesmaller size by using the SAW (surface acoustic wave) filter as theduplexer. In addition, it is also possible, according to the requirementcharacteristics, to implement it by combining the coaxial type, layeredtype and SAW filter.

Moreover, as for the branching circuit of the present invention in theabove-mentioned sixth to fourteenth embodiments, the first internalterminal 103 is the terminal of inputting the transmitting frequencyband of W-CDMA and inputting and outputting the transmitting frequencybands and receiving frequency bands of DCS and GSM, and is the3-frequency branching circuit having the first switching circuit 106 ofswitching between the input of the transmitting frequency band of GSMand the output of the receiving frequency band of GSM branched by abranching circuit 105 and the second switching circuit 107 of switchingbetween the input of the transmitting frequency band of W-CDMA and thetransmitting frequency band of DCS and the output of the receivingfrequency band of DCS branched by a branching circuit 105. However, thebranching circuit of the present invention is not limited thereto, butit may also be the branching circuit characterized by having a firstbranching circuit having the filter function of passing the transmittingfrequency band and the receiving frequency band in each of the first toNth frequency bands and equipped with the first to the k-th internalterminals and the antenna terminal of connecting to the antenna, forinstance, wherein the first internal terminal is the terminal ofinputting the transmitting frequency band of the first frequency band,and also having a second branching circuit, connected to the k-thinternal terminal, of branching the transmitting frequency bands of thefirst frequency band and all or a part of the second to N-th frequencybands.

In addition, as for the branching circuit of the present invention inthe above-mentioned eighteenth to twentieth embodiments, the secondinternal terminal 2304 is the terminal of inputting the transmittingfrequency band of W-CDMA and inputting and outputting the transmittingfrequency band and receiving frequency band of DCS and the firstinternal terminal 2303 is the terminal of inputting and outputting thetransmitting frequency band and the receiving frequency band of GSM, andit is the 3-frequency branching circuit having the second switchingcircuit 2307, connected to the second internal terminal 2304, ofswitching between the input of the transmitting frequency band of W-CDMAand the transmitting frequency band of DCS and the output of thereceiving frequency band of DCS and the first switching circuit 2306,connected to the first internal terminal 2303, of switching between theinput of the transmitting frequency band of GSM and the output of thereceiving frequency band of GSM.

In short, the branching circuit of the present invention should be thebranching circuit characterized by having first branching circuit havingthe filter function of passing the transmitting frequency band and thereceiving frequency band in each of the first to Nth frequency bands andequipped with the first to the k-th internal terminals and the antennaterminal of connecting to the antenna, wherein the first internalterminal is the terminal of outputting the receiving frequency band ofthe first frequency band, and the k-th internal terminal is theinput/output terminal of inputting the transmitting frequency band ofthe first frequency band and inputting and outputting the transmittingfrequency bands and the receiving frequency bands of all or a part ofthe second to N-th frequency bands.

In addition, the branching circuit of the present invention may also bethe branching circuit having replaced the roles of the input and outputin such a branching circuit. To be more specific, the branching circuitof the present invention may also be the branching circuit characterizedby having first branching circuit having the filter function of passingthe transmitting frequency band and the receiving frequency band in eachof the first to Nth frequency bands and equipped with the first to thek-th internal terminals and the antenna terminal of connecting to theantenna, wherein the first internal terminal is the terminal ofinputting the transmitting frequency band of the first frequency band,and the k-th internal terminal is the input/output terminal ofoutputting the receiving frequency band of the first frequency band andinputting and outputting the transmitting frequency bands and thereceiving frequency bands of all or a part of the second to N-thfrequency bands.

As for the branching circuit of the present invention in the case oftaking the circuit configuration described above, the receiving signal(or transmitting signal) to the first internal terminal is branchedfirst by the first branching circuit around the antenna, and so thereceiving signal can be received in a low-loss state so that high tonequality of the receiving signal (or transmitting signal) can be assuredfor instance.

In addition, as it can simultaneously transmit and receive the signal byutilizing the first internal terminal which is the terminal dedicated tothe receiving signal (or transmitting signal), it also supports thesystem in which the W-CDMA (Wide-band Code Division Multiple Access)method is mixed. As a matter of course, a plurality of such terminalsdedicated to the receiving signal (or transmitting signal) may beprovided so that high tone quality of the receiving signal (ortransmitting signal) on each terminal can be assured, for instance.

Moreover, as for the branching circuit of the present invention, it goeswithout saying that it is possible, by further having an arbitrarynumber of the branching circuit in the subsequent stage of theaforementioned first and/or second branching circuit, to branch thereceiving frequency bands and the transmitting frequency bands in anarbitrary number of the frequency bands.

In addition, as for the branching circuit according to theabove-mentioned fifteenth to seventeenth embodiments of the presentinvention, the fourth internal terminal 1907 is the terminal ofinputting the transmitting frequency band of W-CDMA and inputting andoutputting the transmitting frequency band and the receiving frequencyband of DCS, and is the 3-frequency branching circuit having a firstswitching circuit 1904, connected to the first internal terminal 1903,of switching between the input of the transmitting frequency band of GSMand the output of the receiving frequency band of GSM and a secondswitching circuit 1909, connected to the fourth internal terminal 1907,of switching between the input of the transmitting frequency band ofW-CDMA and the transmitting frequency band of DCS and the output of thereceiving frequency band of DCS.

However, the branching circuit of the present invention is not limitedthereto, but it may also be, for instance, the branching circuitcharacterized by having the first branching circuit having the filterfunction of passing the transmitting frequency band and receivingfrequency band in each of the first to Nth frequency bands and equippedwith the first and second internal terminals and the antenna terminal ofconnecting to the antenna, and the second branching circuit having thefilter function of passing the transmitting frequency band and receivingfrequency band in each of the first to N−1-th frequency bands andequipped with the connection terminals of connecting to the third to thek-th internal terminals and to the second internal terminal, and thethird branching circuit, connected to the third internal terminal, ofbranching the transmitting frequency band in the first frequency bandand the frequency bands of all or a part of the second to N-th frequencybands.

In short, the branching circuit of the present invention should be thebranching circuit characterized by having the first branching circuithaving the filter function of passing the transmitting frequency bandand the receiving frequency band in each of the first to Nth frequencybands and equipped with the first and second internal terminals and theantenna terminal of connecting to the antenna and the second branchingcircuit having the filter function of passing the transmitting frequencyband and receiving frequency band in each of the first to N−1-thfrequency bands and equipped with the third to the k-th internalterminals and the connection terminal of connecting to the secondinternal terminal, wherein the first internal terminal is the terminalof inputting and outputting the transmitting frequency band and thereceiving frequency band of the N-th frequency band, the second internalterminal is the terminal of inputting and outputting the transmittingfrequency band and the receiving frequency band of the first to N−1-thfrequency band, and the k-th internal terminal is the terminal ofoutputting the receiving frequency band of the first frequency band, andthe third internal terminal is the input/output terminal of inputtingthe transmitting frequency band of the first frequency band andinputting and outputting the transmitting frequency bands and thereceiving frequency bands of all or a part of the second to N−1-thfrequency bands.

In addition, the branching circuit of the present invention may also bethe branching circuit having replaced the roles of the input and outputin such a branching circuit. To be more specific, the branching circuitof the present invention may also be the branching circuit characterizedby having the first branching circuit having the filter function ofpassing the transmitting frequency band and the receiving frequency bandin each of the first to Nth frequency bands and equipped with the firstand second internal terminals and the antenna terminal of connecting tothe antenna, the second branching circuit having the filter function ofpassing the transmitting frequency band and the receiving frequency bandin each of the first to N−1-th frequency bands and equipped with thethird to k-th internal terminals and the connection terminal ofconnecting to the second internal terminal, wherein the first internalterminal is the terminal of inputting and outputting the transmittingfrequency band and the receiving frequency band of the N-th frequencyband, the second internal terminal is the terminal of inputting andoutputting the transmitting frequency band and the receiving frequencyband of the first to N−1-th frequency band, and the k-th internalterminal is the terminal of inputting the transmitting frequency band ofthe first frequency band, and the third internal terminal is theterminal of outputting the receiving frequency band of the firstfrequency band and inputting and outputting the transmitting frequencybands and the receiving frequency bands of all or a part of the secondto N−1-th frequency bands.

As for the branching circuit of the present invention in the case oftaking the circuit configuration described above, the transmitting andreceiving signal to the first internal terminal is branched first by thefirst branching circuit around the antenna portion, and so thetransmitting and receiving signal can be received in a low-loss state sothat the high tone quality thereof can be assured for instance. As amatter of course, a plurality of terminals dedicated to the transmittingand receiving signals of a plurality of connection methods may beprovided so that the high tone quality of the transmitting and receivingsignals of the plurality of connection methods can be assured forinstance.

In addition, as it can simultaneously transmit and receive the signal byutilizing the k-th internal terminal which is dedicated to outputtingthe receiving frequency band of the first frequency band (or inputtingthe transmitting frequency band of the first frequency band), it alsosupports the system in which the W-CDMA (Wide-band Code DivisionMultiple Access) method is mixed. As a matter of course, a plurality ofsuch terminals dedicated to the receiving signal (or the transmittingsignal) may be provided so that high tone quality of the receivingsignal (or the transmitting signal) on each terminal can be assured forinstance.

Moreover, as for the branching circuit of the present invention, it goeswithout saying that it is possible, by further having an arbitrarynumber of the branching circuit in the subsequent stage of theaforementioned first and/or second branching circuit and/or thirdbranching circuit, to branch the receiving frequency bands and thetransmitting frequency bands in an arbitrary number of the frequencybands.

In addition, the mobile communication equipment (radio communicationequipment) of the present invention is characterized by having theantenna of transmitting and receiving the signal, the branching circuitof the present invention (3-frequency branching circuit) of inputtingand outputting the transmitted and received signal, and the signalprocessing device of processing the signal branched by the branchingcircuit (3-frequency branching circuit).

Thus, the present invention allows the simultaneous receiving of W-CDMA,GSM and DCS by, for instance, using the duplexer around the antennaportion so as to branch the W-CDMA receiving signal first and branch theGSM transmitting and receiving signal from the W-CDMA transmittingsignal and the DCS transmitting and receiving signal by using thebranching circuit of branching the low frequency band and high frequencyband. Furthermore, it is possible to provide the low-pass filter ofpassing the low frequency through the common terminal of thetransmitting and receiving signal of GSM, the transmitting signal ofW-CDMA and transmitting and receiving signal of DCS and the high-passfilter of passing the high frequency through it, and provide the circuitof dividing the transmitting and receiving signals of GSM on thelow-pass filter side, and also provide the circuit of dividing thetransmitting and receiving as to the transmitting signals of W-CDMA andDCS and the transmitting signal of DCS on the high-pass filter side soas to allow the transmitting and receiving of the three frequencies. Inaddition, it is possible, according to the requirement characteristics,to implement the 3-frequency branching circuit of the smaller size andreduced losses by using in the duplexer portion the coaxial typeduplexer using the coaxial type resonator if reduction in losses isrequired, the duplexer of the layered type or using the SAW filter ifthe smaller size is required, and further combining them.

In addition, it is also possible to implement the transmitting andreceiving of the three frequencies by providing in the antenna portionthe low-pass filter of passing the low frequency through the commonterminal of the transmitting and receiving signal of GSM, thetransmitting signal of W-CDMA and transmitting and receiving signal ofDCS and the high-pass filter of passing the high frequency through it,and providing the circuit of dividing the transmitting and receivingsignals of GSM on the low-pass filter side and also providing thecircuit of dividing the transmitting and receiving as to thetransmitting signals of W-CDMA and DCS and the receiving signal of DCSon the high-pass filter side, and it is also feasible to provide the3-frequency branching circuit of the smaller size and reduced losses byusing the aforementioned coaxial type duplexer and the layered and SAWfilter.

Moreover, the entire disclosure of the above literature is quoted as-isso as to be integrated herein.

INDUSTRIAL APPLICABILITY

As is apparent from the above description, the present invention has anadvantage that it can provide the 3-frequency branching circuit,branching circuit and radio communication equipment also usable for thesystem wherein the TDMA method and the W-CDMA method assuring high tonequality and high speed data communication for instance are mixed.

1. A 3-frequency branching circuit having a filter function of passing atransmitting frequency band and a receiving frequency band in each offirst, second and third frequency bands, comprising: first, second andthird internal terminals; an antenna terminal of connecting to anantenna; branching means having a first filter of passing the thirdfrequency band between said first internal terminal and said antennaterminal and a second filter of passing said first and second frequencybands between said second internal terminal and said antenna terminal; afirst switching circuit, connected to said first internal terminal, ofswitching between a first transmitting terminal used to transmit saidthird frequency band and a first receiving terminal used to receive saidthird frequency band; a second switching circuit, connected to saidsecond internal terminal, of switching among a second transmittingterminal used to transmit a transmitting frequency band of said secondfrequency band, a second receiving terminal used to receive a receivingfrequency band of said second frequency band, and the third internalterminal used to transmit and receive said first frequency band; and aduplexer, connected to said third internal terminal, of branching thetransmitting frequency band and the receiving frequency band of saidfirst frequency band.
 2. A 3-frequency branching circuit having a filterfunction of passing a transmitting frequency band and a receivingfrequency band in each of first, second and third frequency bands,comprising: first, second, third and fourth internal terminals; anantenna terminal of connecting to an antenna; branching means having afirst filter of passing said third frequency band between said firstinternal terminal and said antenna terminal and a second filter ofpassing said first and second frequency bands between said secondinternal terminal and said antenna terminal; a first switching circuit,connected to said first internal terminal, of switching between thetransmitting frequency band and the receiving frequency band of saidthird frequency band; a second switching circuit, connected to saidsecond internal terminal, of switching and transmitting the secondfrequency band to the third internal terminal and the first frequencyband to the fourth internal terminal; a third switching circuit,connected to said third internal terminal, of switching between thetransmitting frequency band and the receiving frequency band of saidsecond transmitting frequency band; and a duplexer, connected to saidfourth internal terminal, of branching the transmitting frequency bandand the receiving frequency band of said first frequency band.
 3. A3-frequency branching circuit comprising: a duplexer having a filterfunction of passing a transmitting frequency band and a receivingfrequency band in each of first, second and third frequency bands andequipped with first and second internal terminals, an antenna terminalof connecting to an antenna, a first filter of passing transmittingfrequency bands of said three frequency bands and receiving frequencybands of said second and third frequency bands between said firstinternal terminal and said antenna terminal, and a second filter ofpassing the receiving frequency band of said first frequency bandbetween said second internal terminal and said antenna terminal;branching means, connected to said first internal terminal, of branching(1) the transmitting frequency band of said first frequency band,transmitting frequency band of said second frequency band, and receivingfrequency band of said second frequency band, (2) the transmittingfrequency band of said third frequency band and the receiving frequencyband of said third frequency band; a first switching circuit ofswitching between transmitting of said third frequency band andreceiving of said third frequency band; and a second switching circuitof switching between transmitting of said first and second frequencybands and receiving of said second frequency band.
 4. A 3-frequencybranching circuit comprising: branching means, having a filter functionof passing a transmitting frequency band and a receiving frequency bandin each of first, second and third frequency bands, of branching (1) thetransmitting frequency band and receiving frequency band of said thirdfrequency band, (2) the transmitting frequency band of said first andsecond frequency bands and the receiving frequency band of said firstand second frequency bands, having first and second internal terminals,an antenna terminal of connecting to an antenna, a first filter ofpassing the transmitting frequency band and receiving frequency band ofthe third frequency band between said first internal terminal and saidantenna terminal and a second filter of passing the transmittingfrequency band of said first and second frequency bands and thereceiving frequency band of said first and second frequency bandsbetween said second internal terminal and said antenna terminal; a firstswitching circuit, connected to said first internal terminal, ofswitching between transmitting of said third frequency band andreceiving of said third frequency band; a duplexer, connected to saidsecond internal terminal, having third and fourth internal terminals, athird filter of passing the transmitting frequency band of said firstand second frequency bands and the receiving frequency band of saidsecond frequency band between said third internal terminal and saidsecond internal terminal, and a fourth filter of passing the receivingfrequency band of said first frequency band between said fourth internalterminal and said second internal terminal; and a second switchingcircuit, connected to said third internal terminal, of switching betweenthe transmitting frequency band of said first and second frequency bandsand the receiving frequency band of said second frequency band.
 5. The3-frequency branching circuit according to any one of claims 1, 2, 3 and4, wherein said branching means is constituted by a layeredconfiguration using the dielectric green sheet.
 6. A 3-frequencybranching circuit comprising: a duplexer having a filter function ofpassing a transmitting frequency band and a receiving frequency band ineach of first, second and third frequency bands and equipped with first,second and third internal terminals, an antenna terminal of connectingto an antenna, a first filter of passing a transmitting frequency bandand a receiving frequency band of said third frequency band between saidfirst internal terminal and said antenna terminal, a second filter ofpassing the transmitting frequency band of said first and secondfrequency bands and the receiving frequency band of said secondfrequency band between said second internal terminal and said antennaterminal, and a third filter of passing the receiving frequency band ofsaid first frequency band between said third internal terminal and saidantenna terminal; a first switching circuit, connected to said firstinternal terminal, of switching between the transmitting frequency bandand the receiving frequency band of said third frequency band; and asecond switching circuit, connected to said second internal terminal, ofswitching between the transmitting frequency band of said first andsecond frequency bands and the receiving frequency band of said secondfrequency band.
 7. The 3-frequency branching circuit according to anyone of claims 1, 2, 3, 4 and 6, wherein at least one of said first,second and third switching circuits, said duplexer and said first,second and third filters is constituted by a layered configuration usinga dielectric green sheet.
 8. The 3-frequency branching circuit accordingto any one of claims 1, 2, 3, 4 and 6, wherein at least one of saidbranching means, said first, second and third switching circuits, saidduplexer and said first, second and third filters is constituted bymounting a switching element on a multilayered product using adielectric green sheet.
 9. The 3-frequency branching circuit accordingto any one of claims 1, 2, 3, 4 and 6, wherein at least one of saidfirst, second and third switching circuits has a configuration using adiode.
 10. The 3-frequency branching circuit according to any one ofclaims 1, 2, 3, 4 and 6, wherein a GaAs (gallium arsenide) switch isused for at least one of said branching means and said first, second andthird switching circuits.
 11. The 3-frequency branching circuitaccording to any one of claims 1, 2, 3, 4 and 6, wherein said firstfrequency band is a frequency band supporting the W-CDMA method. 12.Radio communication equipment comprising: an antenna of transmitting andreceiving a signal; a 3-frequency branching circuit according to any oneof claims 1, 2, 3, 4 and 6; and signal processing means of processingthe signal branched by said 3-frequency branching circuit.
 13. Abranching circuit having a filter function of passing a transmittingfrequency band and a receiving frequency band in each of a first to Nthfrequency bands, comprising: first and second internal terminals; anantenna terminal of connecting to an antenna; branching means having afirst filter of passing n+1-th (2≦n≦N−1) to Nth frequency bands betweensaid first internal terminal and said antenna terminal and a secondfilter of passing the first to said nth frequency bands between saidsecond internal terminal and the antenna terminal; a first switchingcircuit, connected to said first internal terminal, of switching betweenthe transmitting frequency bands and the receiving frequency bands ofsaid n+1-th to Nth frequency bands; a second switching circuit,connected to said second internal terminal, of switching between thetransmitting frequency bands of said first frequency band and saidsecond to nth frequency bands and the receiving frequency bands of saidsecond to the nth frequency bands; and a duplexer of branching thetransmitting frequency band and the receiving frequency band of saidfirst frequency band.
 14. A branching circuit having a filter functionof passing a transmitting frequency band and a receiving frequency bandin each of first to Nth frequency bands, comprising: first, second,third and fourth internal terminals; an antenna terminal of connectingto an antenna; branching means having a first filter of passing saidn+1-th (2≦n≦N−1) to Nth frequency bands between said first internalterminal and said antenna terminal and a second filter of passing saidfirst to said nth frequency bands between said second internal terminaland the antenna terminal; a first switching circuit, connected to saidfirst internal terminal, of switching among the frequency bands of saidn+1-th to Nth frequency bands; a second switching circuit, connected tosaid second internal terminal, of switching and transmitting the secondto n-th frequency bands to said third internal terminal and the firstfrequency band to said fourth internal terminal; a third switchingcircuit, connected to said third internal terminal, of switching amongsaid second to n-th frequency bands; and a duplexer, connected to saidfourth internal terminal, of branching the transmitting frequency bandand the receiving frequency band of said first frequency band.
 15. Abranching circuit having a first branching means having a filterfunction of passing a transmitting frequency band and a receivingfrequency band in each of first to Nth frequency bands, and equippedwith first to k-th internal terminals and an antenna terminal ofconnecting to an antenna, wherein said first internal terminal is aterminal of outputting the receiving frequency band of said firstfrequency band; said k-th internal terminal is the terminal of inputtingthe transmitting frequency band of said first frequency band andinputting and outputting the transmitting frequency bands and thereceiving frequency bands of all or a part of the second to said N-thfrequency bands.
 16. A branching circuit comprising: first branchingmeans having a filter function of passing a transmitting frequency bandand a receiving frequency band in each of first to Nth frequency bands,and equipped with first to k-th internal terminals and an antennaterminal of connecting to an antenna, and wherein said first internalterminal is a terminal of inputting the transmitting frequency band ofsaid first frequency band; said k-th internal terminal is the terminalof outputting the receiving frequency band of said first frequency bandand inputting and outputting the transmitting frequency bands and thereceiving frequency bands of all or a part of the second to N-thfrequency bands.
 17. A branching circuit comprising: first branchingmeans having a filter function of passing a transmitting frequency bandand a receiving frequency band in each of first to Nth frequency bands,and equipped with first and second internal terminals and an antennaterminal of connecting to an antenna; and second branching means havinga filter function of passing the transmitting frequency band and thereceiving frequency band in each of first to N−1-th frequency bands, andequipped with third to k-th internal terminals and a connection terminalof connecting to said second internal terminal, wherein said firstinternal terminal is a terminal of inputting and outputting thetransmitting frequency bands and the receiving frequency bands of saidN-th frequency bands; said second internal terminal is a terminal ofinputting and outputting the transmitting frequency band and thereceiving frequency band of said first to said N−1-th frequency bands;said k-th internal terminal is the terminal of outputting the receivingfrequency band of said first frequency band; and said third internalterminal is the terminal of inputting the transmitting frequency band ofsaid first frequency band and inputting and outputting the transmittingfrequency bands and the receiving frequency bands of all or a part ofsaid second to N−1-th frequency bands.
 18. A branching circuitcomprising: first branching means having a filter function of passing atransmitting frequency band and a receiving frequency band in each offirst to Nth frequency bands, and equipped with first and secondinternal terminals and an antenna terminal of connecting to an antenna;and second branching means having a filter function of passing thetransmitting frequency band and the receiving frequency band in each offirst to N−1-th frequency bands, and equipped with third to k-thinternal terminals and a connection terminal of connecting to saidsecond internal terminal, wherein said first internal terminal is aterminal of inputting and outputting the transmitting frequency band andthe receiving frequency band of said N-th frequency band; said secondinternal terminal is the terminal of inputting and outputting thetransmitting frequency band and the receiving frequency band of saidfirst to said N−1-th frequency bands; said k-th internal terminal is theterminal of inputting the transmitting frequency band of said firstfrequency band; and said third internal terminal is the terminal ofoutputting the receiving frequency band of said first frequency band andinputting and outputting all or a part of the transmitting frequencybands and the receiving frequency bands of said second to N−1-thfrequency bands.
 19. Radio communication equipment comprising: anantenna of transmitting and receiving a signal; a branching circuitaccording to any one of claims 13, 14, 15, 16, 17 and 18; and signalprocessing means of processing the signal branched by said branchingcircuit.
 20. The 3-frequency branching circuit according to claim 1,wherein said third internal terminal is connected to said branchingmeans and is also grounded via a diode.
 21. The 3-frequency branchingcircuit according to claim 1, wherein said third internal terminal isconnected to said branching means via the diode in a forward directionwhen transmitting and receiving said first frequency band.
 22. The3-frequency branching circuit according to claim 1, further comprising alow-pass filter inserted between said branching means and said secondswitching circuit.
 23. The 3-frequency branching circuit according toclaim 1, wherein said first receiving terminal and said third internalterminal are connected to said antenna and are also grounded via thediode in a forward direction and a grounding resistor respectively; andone resistor is shared as the grounding resistor used for saidrespective groundings.
 24. The 3-frequency branching circuit accordingto claim 1, wherein said first and second receiving terminals areconnected to said antenna and are also grounded via the diode in aforward direction and a grounding resistor respectively; and oneresistor is shred as the grounding resistor used for said respectivegroundings.
 25. The 3-frequency branching circuit according to claim 2,wherein that said duplexer has a configuration in which a coaxial typeresonator is used and is comprised of a notch filter and a band passfilter.
 26. The 3-frequency branching circuit according to claim 25,wherein said duplexer has the configuration in which a coaxial typeresonator is used, and a signal of a transmitting frequency band istransmitted to said fourth internal terminal via said notch filter, anda signal of a receiving frequency band is transmitted from said fourthinternal terminal via said band pass filter.
 27. The 3-frequencybranching circuit according to claim 2, wherein said fourth internalterminal is an internal terminal of a multilayered product.
 28. The3-frequency branching circuit according to claim 2, wherein a SAW filteris used for said duplexer.
 29. The 3-frequency branching circuitaccording to claim 2, wherein said duplexer is comprised of a coaxialtype resonator and a layered filter.
 30. The 3-frequency branchingcircuit according to claim 2, wherein a coaxial type resonator and a SAWfilter are used for said duplexer.
 31. The 3-frequency branching circuitaccording to claim 2, wherein a layered filter and a SAW filter are usedfor said duplexer.
 32. The 3-frequency branching circuit according toclaim 3, wherein said duplexer has a configuration using a coaxial typeresonator, said first filter is comprised of a notch filter and saidsecond filter is comprised of a band pass filter.
 33. The 3-frequencybranching circuit according to claim 3, wherein said duplexer has aconfiguration using a coaxial type resonator, and a notch filter and alow-pass filter are constituted between said first internal terminal andsaid antenna terminal.
 34. The 3-frequency branching circuit accordingto claim 3, wherein said duplexer has a configuration using a coaxialtype resonator between said first internal terminal and said antennaterminal, and said second filter is comprised of a layered filter. 35.The 3-frequency branching circuit according to claim 3, wherein saidduplexer has a configuration using a coaxial type resonator between saidfirst internal terminal and said antenna terminal, and a SAW filter isused for said second filter.
 36. The 3-frequency branching circuitaccording to claim 3, wherein said duplexer has a configuration using alayered filter between said first internal terminal and said antennaterminal, and a SAW filter is used between said second terminal and saidantenna terminal.
 37. The 3-frequency branching circuit according toclaim 4, wherein said duplexer has a configuration using a coaxial typeresonator, and said third filter is comprised of a notch filter and saidfifth filter is comprised of a band pass filter.
 38. The 3-frequencybranching circuit according to claim 4, wherein said duplexer has aconfiguration using a coaxial type resonator, and said third filter iscomprised of a notch filter and a low-pass filter.
 39. The 3-frequencybranching circuit according to claim 4, wherein said duplexer has aconfiguration using a layered filter, where the layered filterconstituted between said third internal terminal and said secondinternal terminal is comprised of a notch filter and the layered filterconstituted between said fourth internal terminal and said secondinternal terminal is comprised of a band pass filter.
 40. The3-frequency branching circuit according to claim 4, wherein saidduplexer has a configuration using a layered filter, where the layeredfilter constituted between said third internal terminal and said secondinternal terminal is comprised of a notch filter and a low-pass filter.41. The 3-frequency branching circuit according to claim 4, wherein saidduplexer is comprised of a filter using a coaxial type resonator betweensaid third internal terminal and said second internal terminal, and saidfourth filter is comprised of a layered filter.
 42. The 3-frequencybranching circuit according to claim 4, wherein said duplexer iscomprised of a filter using a coaxial type resonator between said thirdinternal terminal and said second internal terminal, and the filterconstituted between said fourth internal terminal and said secondinternal terminal is comprised of a SAW filter.
 43. The 3-frequencybranching circuit according to claim 4, wherein said duplexer has saidthird filter comprised of a layered filter and said fourth filter iscomprised of a SAW filter.
 44. The 3-frequency branching circuitaccording to claim 6, wherein said first filter is formed by a low-passfilter, said second filter is formed by a band pass filter, and saidthird filter is formed by a high-pass filter.
 45. The 3-frequencybranching circuit according to claim 6, wherein said first filter isformed by a low-pass filter, said second filter is formed by a band passfilter, and said third filter is formed by a notch filter.
 46. Thebranching circuit according to claim 15, further comprising a secondbranching means, connected to said k-th internal terminal, of branchingthe transmitting frequency band of said first frequency band and all ora part of the frequency bands of said second to said N-th frequencybands.
 47. The branching circuit according to claim 46, wherein said Nis 3 and said k is 2; said second internal terminal is the terminal ofinputting the transmitting frequency band of said first frequency bandand inputting and outputting the transmitting frequency bands and thereceiving frequency bands of said second and third frequency bands whichare all of said frequency bands; a first switching circuit of switchingbetween input of the transmitting frequency band of said third frequencyband and output of the receiving frequency band of said third frequencyband branched by said second branching means; and a second switchingcircuit of switching between the input of the transmitting frequencyband of said first frequency band and the transmitting frequency band ofsaid second frequency band and the output of the receiving frequencyband of said second frequency band branched by said second branchingmeans.
 48. The branching circuit according to claim 15, wherein said Nis 3 and said k is 2; said third internal terminal is a terminal ofinputting the transmitting frequency band of said first frequency bandand inputting and outputting the transmitting frequency band and thereceiving frequency band of said second frequency band which is saidpart of frequency bands; said second internal terminal is the terminalof inputting and outputting the transmitting frequency band and thereceiving frequency band of said third frequency band which is theremaining frequency band; a second switching circuit, connected to saidthird internal terminal, of switching between the input of thetransmitting frequency band of said first frequency band and thetransmitting frequency band of said second frequency band and the outputof the receiving frequency band of said second frequency band; and afirst switching circuit, connected to said second internal terminal, ofswitching between the input of the transmitting frequency band of saidthird frequency band and the output of the receiving frequency band ofsaid third frequency band.
 49. The branching circuit according to claim17, further comprising third branching means, connected to said thirdinternal terminal, of branching the transmitting frequency band of saidfirst frequency band and all or a part of said second to N-th frequencybands.
 50. The branching circuit according to claim 17, wherein said Nis 3 and said k is 4; said third internal terminal is the terminal ofinputting the transmitting frequency band of said first frequency bandand inputting and outputting the transmitting frequency band and thereceiving frequency band of said second frequency band which is all ofsaid frequency bands; a first switching circuit, connected to said firstinternal terminal, of switching between the input of the transmittingfrequency band of said third frequency band and the output of thereceiving frequency band of said third frequency band; and a secondswitching circuit, connected to said third internal terminal, ofswitching between the input of the transmitting frequency band of saidfirst frequency band and the transmitting frequency band of said secondfrequency band and the output of the receiving frequency band of saidsecond frequency band.